postfix-3.11-20250709-nonprod

postfix/.indent.pro

@@ -307,7 +307,6 @@
 -TRESPONSE
 -TREST_TABLE
 -TRES_CONTEXT
--TRING
 -TRWR_CONTEXT
 -TSCACHE
 -TSCACHE_CLNT

postfix/.indent.pro.orig

@@ -0,0 +1,450 @@
+-TABOUNCE_STATE
+-TADDR_MATCH_LIST
+-TADDR_PATTERN
+-TALIAS_TOKEN
+-TANVIL_CLNT
+-TANVIL_LOCAL
+-TANVIL_MAX
+-TANVIL_REMOTE
+-TANVIL_REQ_TABLE
+-TARGV
+-TASN1_INTEGER
+-TASN1_OBJECT
+-TATTR_CLNT
+-TATTR_OVER_INT
+-TATTR_OVER_STR
+-TATTR_OVER_TIME
+-TATTR_TABLE
+-TAUTHORITY_KEYID
+-TAUTO_CLNT
+-TBH_TABLE
+-TBINATTR
+-TBINATTR_INFO
+-TBINHASH
+-TBINHASH_INFO
+-TBIO
+-TBOUNCE_INFO
+-TBOUNCE_LOG
+-TBOUNCE_LOG_DSN_BUF
+-TBOUNCE_LOG_FORGE
+-TBOUNCE_LOG_RCPT_BUF
+-TBOUNCE_STAT
+-TBOUNCE_STR_PARAMETER
+-TBOUNCE_TEMPLATE
+-TBOUNCE_TEMPLATES
+-TBOUNCE_TIME_DIVISOR
+-TBOUNCE_TIME_PARAMETER
+-TBYTE_MASK
+-TCFG_PARSER
+-TCIDR_MATCH
+-TCLEANUP_REGION
+-TCLEANUP_STATE
+-TCLEANUP_STAT_DETAIL
+-TCLIENT_LIST
+-TCLNT_STREAM
+-TCONFIG_BOOL_FN_TABLE
+-TCONFIG_BOOL_TABLE
+-TCONFIG_INT_FN_TABLE
+-TCONFIG_INT_TABLE
+-TCONFIG_LONG_FN_TABLE
+-TCONFIG_LONG_TABLE
+-TCONFIG_NBOOL_FN_TABLE
+-TCONFIG_NBOOL_TABLE
+-TCONFIG_NCODE_TABLE
+-TCONFIG_NINT_FN_TABLE
+-TCONFIG_NINT_TABLE
+-TCONFIG_RAW_FN_TABLE
+-TCONFIG_RAW_TABLE
+-TCONFIG_STR_FN_TABLE
+-TCONFIG_STR_TABLE
+-TCONFIG_TIME_FN_TABLE
+-TCONFIG_TIME_TABLE
+-TCONST_CHAR_STAR
+-TCRYPTO_EX_DATA
+-TCTABLE
+-TCTABLE_ENTRY
+-TDB_COMMON_CTX
+-TDELIVERED_HDR_INFO
+-TDELIVER_ATTR
+-TDELIVER_REQUEST
+-TDELTA_TIME
+-TDICT
+-TDICT_CACHE
+-TDICT_CACHE_SREQ
+-TDICT_CACHE_SREQ_INFO
+-TDICT_CACHE_TEST
+-TDICT_CDBM
+-TDICT_CDBQ
+-TDICT_CIDR
+-TDICT_CIDR_ENTRY
+-TDICT_DB
+-TDICT_DBM
+-TDICT_DEBUG
+-TDICT_ENV
+-TDICT_FAIL
+-TDICT_FINAL_WRAPPER
+-TDICT_HT
+-TDICT_INLINE
+-TDICT_LDAP
+-TDICT_LMDB
+-TDICT_MC
+-TDICT_MONGODB
+-TDICT_MYSQL
+-TDICT_NI
+-TDICT_NIS
+-TDICT_NISPLUS
+-TDICT_NODE
+-TDICT_OPEN_EXTEND_FN
+-TDICT_OPEN_FN
+-TDICT_OPEN_INFO
+-TDICT_OWNER
+-TDICT_PCRE
+-TDICT_PCRE_ENGINE
+-TDICT_PCRE_EXPAND_CONTEXT
+-TDICT_PCRE_IF_RULE
+-TDICT_PCRE_MATCH_RULE
+-TDICT_PCRE_PRESCAN_CONTEXT
+-TDICT_PCRE_REGEXP
+-TDICT_PCRE_RULE
+-TDICT_PGSQL
+-TDICT_PIPE
+-TDICT_PROXY
+-TDICT_RAND
+-TDICT_RANDOM
+-TDICT_REGEXP
+-TDICT_REGEXP_EXPAND_CONTEXT
+-TDICT_REGEXP_IF_RULE
+-TDICT_REGEXP_MATCH_RULE
+-TDICT_REGEXP_PATTERN
+-TDICT_REGEXP_PRESCAN_CONTEXT
+-TDICT_REGEXP_RULE
+-TDICT_SDBM
+-TDICT_SOCKMAP
+-TDICT_SOCKMAP_REFC_HANDLE
+-TDICT_SQLITE
+-TDICT_STATIC
+-TDICT_SURROGATE
+-TDICT_TCP
+-TDICT_TEXT
+-TDICT_THASH
+-TDICT_UNION
+-TDICT_UNIX
+-TDICT_UTF8_BACKUP
+-TDICT_WRAPPER
+-TDNS_FIXED
+-TDNS_REPLY
+-TDNS_RR
+-TDOMAIN_LIST
+-TDSN
+-TDSN_BUF
+-TDSN_FILTER
+-TDSN_SPLIT
+-TDSN_STAT
+-TDYMAP_INFO
+-TEC_GROUP
+-TEC_KEY
+-TEDIT_FILE
+-TEVENT_MASK
+-TEVP_CIPHER_CTX
+-TEVP_MAC_CTX
+-TEVP_MD
+-TEVP_MD_CTX
+-TEVP_PKEY
+-TEXPAND_ATTR
+-TFILE
+-TFORWARD_INFO
+-THBC_ACTION_CALL_BACKS
+-THBC_CALL_BACKS
+-THBC_CHECKS
+-THBC_MAP_INFO
+-THBC_OUTPUT_CALL_BACKS
+-THBC_TEST_CONTEXT
+-THEADER_OPTS
+-THEADER_TOKEN
+-THMAC_CTX
+-THOST
+-THTABLE
+-THTABLE_INFO
+-TINET_ADDR_LIST
+-TINET_ADDR_SIZES
+-TINET_PROTO_INFO
+-TINSTANCE
+-TINST_SELECTION
+-TINT32_TYPE
+-TINTV
+-TINT_TABLE
+-TJMP_BUF_WRAPPER
+-TLDAP
+-TLDAPMessage
+-TLDAPURLDesc
+-TLDAP_CONN
+-TLIB_DP
+-TLIB_FN
+-TLMTP_ATTR
+-TLMTP_RESP
+-TLMTP_SESSION
+-TLMTP_STATE
+-TLOCAL_EXP
+-TLOCAL_STATE
+-TLOGIN_SENDER_MATCH
+-TLOGWRITER
+-TLONG_NAME_MASK
+-TMAC_EXP_CONTEXT
+-TMAC_EXP_OP_INFO
+-TMAC_HEAD
+-TMAC_PARSE
+-TMAIL_ADDR_FORMATTER
+-TMAIL_ADDR_MAP_TEST
+-TMAIL_PRINT
+-TMAIL_SCAN
+-TMAIL_STREAM
+-TMAIL_VERSION
+-TMAI_HOSTADDR_STR
+-TMAI_HOSTNAME_STR
+-TMAI_SERVNAME_STR
+-TMAI_SERVPORT_STR
+-TMAPS
+-TMAP_SEARCH
+-TMASTER_INT_WATCH
+-TMASTER_PROC
+-TMASTER_SERV
+-TMASTER_STATUS
+-TMASTER_STR_WATCH
+-TMATCH_LIST
+-TMATCH_OPS
+-TMBLOCK
+-TMBOX
+-TMDB_env
+-TMDB_txn
+-TMDB_val
+-TMILTER
+-TMILTER8
+-TMILTERS
+-TMILTER_MACROS
+-TMILTER_MSG_CONTEXT
+-TMIME_ENCODING
+-TMIME_INFO
+-TMIME_STACK
+-TMIME_STATE
+-TMIME_STATE_DETAIL
+-TMIME_TOKEN
+-TMKMAP
+-TMKMAP_DB
+-TMKMAP_DBM
+-TMKMAP_OPEN_EXTEND_FN
+-TMKMAP_OPEN_FN
+-TMKMAP_OPEN_INFO
+-TMKMAP_SDBM
+-TMSG_STATS
+-TMULTI_SERVER
+-TMVECT
+-TMYSQL
+-TMYSQL_NAME
+-TMYSQL_RES
+-TNAMADR_LIST
+-TNAME_ASSIGNMENT
+-TNAME_CODE
+-TNAME_MASK
+-TNBBIO
+-TNVTABLE_INFO
+-TOPTIONS
+-TOSSL_DGST
+-TPCF_DBMS_INFO
+-TPCF_DEPR_PARAM_INFO
+-TPCF_EVAL_CTX
+-TPCF_MASTER_EDIT_REQ
+-TPCF_MASTER_ENT
+-TPCF_MASTER_FLD_REQ
+-TPCF_PARAM_CTX
+-TPCF_PARAM_NODE
+-TPCF_PARAM_TABLE
+-TPCF_SERVICE_DEF
+-TPCF_SERVICE_PATTERN
+-TPCF_STRING_NV
+-TPEER_FROM_HAPROXY_CASE
+-TPEER_FROM_NON_SOCKET_CASE
+-TPEER_FROM_PASS_ATTR_CASE
+-TPEER_FROM_UNCONN_SOCKET_CASE
+-TPEER_NAME
+-TPGSQL_NAME
+-TPICKUP_INFO
+-TPIPE_ATTR
+-TPIPE_PARAMS
+-TPIPE_STATE
+-TPLMYSQL
+-TPLPGSQL
+-TPOSTMAP_KEY_STATE
+-TPOST_MAIL_FCLOSE_STATE
+-TPOST_MAIL_STATE
+-TPRIVATE_STR_TABLE
+-TPSC_CALL_BACK_ENTRY
+-TPSC_CLIENT_INFO
+-TPSC_DNSBL_HEAD
+-TPSC_DNSBL_SCORE
+-TPSC_DNSBL_SITE
+-TPSC_ENDPT_LOOKUP_INFO
+-TPSC_HAPROXY_STATE
+-TPSC_SMTPD_COMMAND
+-TPSC_STARTTLS
+-TPSC_STATE
+-TQMGR_ENTRY
+-TQMGR_FEEDBACK
+-TQMGR_JOB
+-TQMGR_MESSAGE
+-TQMGR_PEER
+-TQMGR_QUEUE
+-TQMGR_RCPT
+-TQMGR_RCPT_LIST
+-TQMGR_RECIPIENT
+-TQMGR_SCAN
+-TQMGR_TRANSPORT
+-TQMQPD_STATE
+-TRCPT_BUF
+-TRECIPIENT
+-TRECIPIENT_LIST
+-TREC_TYPE_NAME
+-TRESOLVE_REPLY
+-TRESPONSE
+-TREST_TABLE
+-TRES_CONTEXT
+-TRWR_CONTEXT
+-TSCACHE
+-TSCACHE_CLNT
+-TSCACHE_MULTI
+-TSCACHE_MULTI_DEST
+-TSCACHE_MULTI_ENDP
+-TSCACHE_MULTI_HEAD
+-TSCACHE_SINGLE
+-TSCACHE_SINGLE_DEST
+-TSCACHE_SINGLE_ENDP
+-TSCACHE_SIZE
+-TSCAN_DIR
+-TSCAN_INFO
+-TSCAN_OBJ
+-TSENDER_LOGIN_MATCH
+-TSERVER_AC
+-TSESSION
+-TSHARED_PATH
+-TSINGLE_SERVER
+-TSINK_COMMAND
+-TSINK_STATE
+-TSLMDB
+-TSMFICTX
+-TSMTPD_CMD
+-TSMTPD_DEFER
+-TSMTPD_ENDPT_LOOKUP_INFO
+-TSMTPD_POLICY_CLNT
+-TSMTPD_PROXY
+-TSMTPD_RBL_EXPAND_CONTEXT
+-TSMTPD_RBL_STATE
+-TSMTPD_RCPTMAP_ST
+-TSMTPD_STATE
+-TSMTPD_TOKEN
+-TSMTPD_XFORWARD_ATTR
+-TSMTP_ADDR
+-TSMTP_CLI_ATTR
+-TSMTP_CMD
+-TSMTP_ITERATOR
+-TSMTP_RESP
+-TSMTP_SASL_AUTH_CACHE
+-TSMTP_SESSION
+-TSMTP_STATE
+-TSMTP_TLS_POLICY
+-TSMTP_TLS_SESS
+-TSMTP_TLS_SITE_POLICY
+-TSM_STATE
+-TSOCKADDR_SIZE
+-TSPAWN_ATTR
+-TSSL
+-TSSL_CTX
+-TSSL_SESSION
+-TSTATE
+-TSTRING_LIST
+-TSTRING_TABLE
+-TSYS_EXITS_DETAIL
+-TTEST_BASE
+-TTEST_CASE
+-TTLSMGR_SCACHE
+-TTLSP_STATE
+-TTLSRPT_WRAPPER
+-TTLS_APPL_STATE
+-TTLS_CERTS
+-TTLS_CLIENT_INIT_PROPS
+-TTLS_CLIENT_PARAMS
+-TTLS_CLIENT_START_PROPS
+-TTLS_DANE
+-TTLS_PKEYS
+-TTLS_PRNG_SEED_INFO
+-TTLS_PRNG_SRC
+-TTLS_ROLE
+-TTLS_SCACHE
+-TTLS_SCACHE_ENTRY
+-TTLS_SERVER_INIT_PROPS
+-TTLS_SERVER_START_PROPS
+-TTLS_SESS_STATE
+-TTLS_TICKET_KEY
+-TTLS_TLSA
+-TTLS_USAGE
+-TTLS_VINFO
+-TTLScontext_t
+-TTOK822
+-TTRANSPORT_INFO
+-TTRIGGER_SERVER
+-TUSER_ATTR
+-TVBUF
+-TVSTREAM
+-TVSTREAM_POPEN_ARGS
+-TVSTRING
+-TWAIT_STATUS_T
+-TWATCHDOG
+-TWATCH_FD
+-TX509
+-TX509V3_CTX
+-TX509_EXTENSION
+-TX509_NAME
+-TX509_STORE_CTX
+-TXSASL_CLIENT
+-TXSASL_CLIENT_CREATE_ARGS
+-TXSASL_CLIENT_IMPL
+-TXSASL_CLIENT_IMPL_INFO
+-TXSASL_CYRUS_CB
+-TXSASL_CYRUS_CLIENT
+-TXSASL_CYRUS_ERROR_INFO
+-TXSASL_CYRUS_SERVER
+-TXSASL_DCSRV_MECH
+-TXSASL_DOVECOT_SERVER
+-TXSASL_DOVECOT_SERVER_IMPL
+-TXSASL_DOVECOT_SERVER_MECHS
+-TXSASL_SERVER
+-TXSASL_SERVER_CREATE_ARGS
+-TXSASL_SERVER_IMPL
+-TXSASL_SERVER_IMPL_INFO
+-Tbind_props
+-Tbson_iter_t
+-Tcipher_probe_t
+-Td2i_X509_t
+-Tdane_digest
+-Tdane_mtype
+-Tfilter_ctx
+-Tgeneral_name_stack_t
+-Tiana_digest
+-Toff_t
+-Tpem_load_state_t
+-Tregex_t
+-Tregmatch_t
+-Tsasl_conn_t
+-Tsasl_secret_t
+-Tsfsistat
+-Tsigset_t
+-Tsize_t
+-Tsockaddr
+-Tsockaddr_storage
+-Tssize_t
+-Tssl_cipher_stack_t
+-Tssl_comp_stack_t
+-Ttime_t
+-Ttlsa_filter
+-Tuint16_t
+-Tuint32_t
+-Tuint8_t
+-Tx509_stack_t

postfix/HISTORY

@@ -28932,7 +28932,7 @@ Apologies for any names omitted.
 	Documentation: updated TLSRPT_README, added postfix-tlspol
 	policy plugin, deprecated the policy_ttl attribute. File:
 	proto/TLSRPT_README.html.
-
+ 
 20250207
 
 	Performance: when a mysql: or pgsql: configuration specifies
@@ -29345,3 +29345,139 @@ Apologies for any names omitted.
 	Cleanup: simplified the rule parser in global/server_acl.c.
 
 	Unbroke dict_debug Valgrind checks. File: util/dict_debug_test.sh.
+
+	Baseline is postfix-3.11-20250709
+
+NONPROD CODE
+
+	Feature: support for the REQUIRETLS verb in SMTP. According
+	to RFC 8689, this requires TLS server certificate matching.
+	Files: cleanup/cleanup_api.c, global/cleanup_strflags.c,
+	global/post_mail.c, global/post_mail.c, global/ehlo_mask.[hc],
+	global/ehlo_mask_test.c, local/forward.c, smtpd/smtpd.c,
+	smtp/smtp_connect.c, smtp/smtp_proto.c.
+
+	Added a configuration parameter "requiretls_enable" (default:
+	yes). Files: cleanup/cleanup_api.c, global/cleanup_strflags.c,
+	global/post_mail.c, global/post_mail.c, global/ehlo_mask.[hc],
+	global/ehlo_mask_test.c, local/forward.c, smtpd/smtpd.c,
+	smtp/smtp_connect.c, smtp/smtp_proto.c.
+
+	After a certificate check fails, or a remote SMTP server
+	does not announce REQUIRETLS support, the Postfix SMTP
+	client will override the RFC 8689 5.x.x.  status and treat
+	it as a soft error, until there are no more alternate MX
+	servers to try. Files: smtp/smtp.h, smtp/smtp_proto.c,
+	smtp/smtp_trouble.c.
+
+	When a message received with REQUIRETLS is returned in a
+	delivery status notification, return the message headers
+	only, and do not request delivery with REQUIRETLS. Files:
+	bounce/bounce_notify_service.c, bounce/bounce_one_service.c,
+	bounce/bounce_trace_service.c, bounce/bounce_verp_service.c,
+	bounce/bounce_warn_service.c.
+
+	Completed: new Postfix sendmail command option "-O requiretls"
+	to request that deliveries over SMTP use the REQUIRETLS
+	extension. The option value "requiretls" is case-insensitive.
+	Files: sendmail/sendmail.c, global/rec_types.h, pickup/pickup.c.
+
+	Cleanup: new Postfix sendmail command option "-O smtputf8"
+	to request that deliveries over SMTP use the SMTPUTF8
+	extension. This reuses logic that was introduced for
+	REQUIRETLS. The option value "smtputf8" is case-insensitive.
+	Files: sendmail/sendmail.c.
+
+	Cleanup: when message delivery requires that a remote SMTP
+	server supports SMTPUTF8, try multiple MX servers before
+	returning a message as undeliverable. This reuses logic
+	that was introduced for REQUIRETLS. File: smtp/smtp_proto.c.
+
+	Completed: support in the pipe(8) daemon to propagate
+	REQUIRETLS through post-queue content filters that pass
+	filtered mail to the Postfix sendmail(1) command. This
+	involves a new a pipe(8) macro ${requiretls} that expands
+	into a suitable sendmail(1) command-line option. A more
+	secretive alternative would be to pass the info with a
+	REQUIRETLS environment variable, but that would require
+	change to the default import_environment setting. Files:
+	pipe/pipe.c, sendmail/sendmail.c.
+
+	Completed: the SMTP/LMTP client with "flags=X" will not
+	require REQUIRETLS support in the final server. Files:
+	smtp/smtp.c, smtp/smtp_proto.c.
+
+	Completed: REQUIRETLS support can be disabled in the Postfix
+	SMTP/LMTP client with "{ -o requiretls_enable = no }". This
+	is recommended for a perimeter MTA that hands off mail to
+	internal servers that may not support REQUIRETLS.
+
+	Completed: smtp_enforce_requiretls list of next-hop domains
+	(or UNIX-domain pathnames) that are ready for REQUIRETLS
+	enforcement. This may help with gradual adoption.
+
+TODO
+
+	Encapsulate the sendopts-to-cleanup-flags mapping.
+
+	Postfix sendmail -O TlsRequired option?
+
+	What REQUIRETLS expectations can we enforce when delivering
+	over a UNIX-domain channel? The SMTP/LMTP client currently
+	implements the same behavior as for TCP, except that
+	opportunistic TLS is converted into 'none'.
+
+	Document how REQUIRETLS works (or does not) with external
+	content filters.
+
+	- REQUIRETLS will not affect Milter-based content filters,
+	  assuming that they don't expose message content via some
+	  side channel.
+
+	- REQUIRETLS can work with smtpd_proxy_filter as long as
+	  - the Postfix SMTP server passes the entire Postfix SMTP
+	    client's MAIL FROM command line through the filter to
+	    the Postfix SMTP server after the proxy filter,
+	  - the post-filter Postfix SMTP server allows REQUIRETLS
+	    in a plaintext session.
+	  The Postfix proxy filter client does not need to require
+	  REQUIRETLS (or SMTPUTF8) announcements in the filter's
+	  EHLO response.
+
+	- REQUIRETLS can work with a local SMTP-based after-queue
+	  content filters as long as
+	  - the filter announces REQUIRETLS in the EHLO response
+	    (this could be 'always', or copied from the after-filter
+	    Postfix SMTP server's EHLO response),
+	  - the filter passes the entire MAIL FROM command from the
+	    before-filter Postfix SMTP client to the after-filter
+	    Postfix SMTP server,
+	  - the post-filter Postfix SMTP server allows MAIL FROM
+	    with REQUIRETLS in a plaintext session.
+	  Apart from that, the content filter does not need to
+	  'know' that REQUIRETLS is active (assuming that it does
+	  not leak message content through some side channel.
+
+	- REQUIRETLS can work with pipe(8)-filter-sendmail(1)
+	  after-queue content filters, by specifying a pipe(8) macro
+	  ${requiretls} which expands to a suitable sendmail(1)
+	  command-line option. Maybe we can also make this work
+	  with a REQUIRETLS environment variable (requires change
+	  to the (Postfix sendmail) import_environment list.
+
+	- The Postfix LMTP client when run with the -X option will
+	  not require that the LMTP server announces REQUIRETLS
+	  support.
+
+	- Perimeter MTA configuration: disable REQUIRETLS (or
+	  REQUIRETLS enforcement) on the inbound relay transport
+	  when internal infrastructure may not be suitable for
+	  REQUIRETLS enforcement.
+
+	If a message contains "TLS-Required: no", should a bounce
+	message also contain this header?
+
+	Ditto for "tls_required_enable = no" and "TLS-Required:
+	no". The header is provided by the sender, and enforcement
+	is up the Postfix SMTP client.
+

postfix/README_FILES/COMPATIBILITY_README

@@ -0,0 +1,459 @@
+PPoossttffiixx BBaacckkwwaarrddss--CCoommppaattiibbiilliittyy SSaaffeettyy NNeett
+
+-------------------------------------------------------------------------------
+
+PPuurrppoossee ooff tthhiiss ddooccuummeenntt
+
+Postfix 3.0 introduces a safety net that runs Postfix programs with backwards-
+compatible default settings after an upgrade. The safety net will log a warning
+whenever a "new" default setting could have an negative effect on your mail
+flow.
+
+This document provides information on the following topics:
+
+  * Detailed descriptions of Postfix backwards-compatibility warnings.
+
+  * What backwards-compatible settings you may have to make permanent in
+    main.cf or master.cf.
+
+  * How to turn off Postfix backwards-compatibility warnings.
+
+OOvveerrvviieeww
+
+With backwards compatibility turned on, Postfix logs a message whenever a
+backwards-compatible default setting may be required for continuity of service.
+Based on this logging the system administrator can decide if any backwards-
+compatible settings need to be made permanent in main.cf or master.cf, before
+turning off the backwards-compatibility safety net as described at the end of
+this document.
+
+Logged with compatibility_level < 1:
+
+  * Using backwards-compatible default setting append_dot_mydomain=yes
+
+  * Using backwards-compatible default setting chroot=y
+
+  * Using backwards-compatible default setting "smtpd_relay_restrictions =
+    (empty)"
+
+  * Using backwards-compatible default setting smtputf8_enable=no
+
+Logged with compatibility_level < 2:
+
+  * Using backwards-compatible default setting mynetworks_style=subnet
+
+  * Using backwards-compatible default setting relay_domains=$mydestination
+
+Logged with compatibility_level < 3.6:
+
+  * Using backwards-compatible default setting smtpd_tls_fingerprint_digest=md5
+
+  * Using backwards-compatible default setting smtp_tls_fingerprint_digest=md5
+
+  * Using backwards-compatible default setting lmtp_tls_fingerprint_digest=md5
+
+  * Using backwards-compatible default setting
+    smtpd_relay_before_recipient_restrictions=no
+
+  * Using backwards-compatible default setting respectful_logging=no
+
+Logged with compatibility_level < 3.11:
+
+  * using backwards-compatible default setting
+    smtp_tlsrpt_skip_reused_handshakes=yes
+
+  * using backwards-compatible default setting xxx_security_level=(empty)
+
+If such a message is logged in the context of a legitimate request, the system
+administrator should make the backwards-compatible setting permanent in main.cf
+or master.cf, as detailed in the sections that follow.
+
+When no more backwards-compatible settings need to be made permanent, the
+system administrator should turn off the backwards-compatibility safety net as
+described at the end of this document.
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg aappppeenndd__ddoott__mmyyddoommaaiinn==yyeess
+
+The append_dot_mydomain default value has changed from "yes" to "no". This
+could result in unexpected non-delivery of email after Postfix is updated from
+an older version. The backwards-compatibility safety net is designed to prevent
+such surprises.
+
+As long as the append_dot_mydomain parameter is left unspecified at its
+implicit default value, and the compatibility_level setting is less than 1,
+Postfix may log one of the following messages:
+
+  * Messages about missing "localhost" in mydestination or other address class:
+
+        postfix/trivial-rewrite[14777]: using backwards-compatible
+            default setting append_dot_mydomain=yes to rewrite
+            "localhost" to "localhost.example.com"; please add
+            "localhost" to mydestination or other address class
+
+    If Postfix logs the above message, add "localhost" to mydestination (or
+    virtual_alias_domains, virtual_mailbox_domains, or relay_domains) and
+    execute the command "ppoossttffiixx rreellooaadd".
+
+  * Messages about incomplete domains in email addresses:
+
+        postfix/trivial-rewrite[25835]: using backwards-compatible
+            default setting append_dot_mydomain=yes to rewrite "foo" to
+            "foo.example.com"
+
+    If Postfix logs the above message for domains different from "localhost",
+    and the sender cannot be changed to use complete domain names in email
+    addresses, then the system administrator should make the backwards-
+    compatible setting "append_dot_mydomain = yes" permanent in main.cf:
+
+        # ppoossttccoonnff aappppeenndd__ddoott__mmyyddoommaaiinn==yyeess
+        # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg cchhrroooott==yy
+
+The master.cf chroot default value has changed from "y" (yes) to "n" (no). The
+new default avoids the need for copies of system files under the Postfix queue
+directory. However, sites with strict security requirements may want to keep
+the chroot feature enabled after updating Postfix from an older version. The
+backwards-compatibility safety net is designed allow the administrator to
+choose if they want to keep the old behavior.
+
+As long as a master.cf chroot field is left unspecified at its implicit default
+value, and the compatibility_level setting is less than 1, Postfix may log the
+following message while it reads the master.cf file:
+
+    postfix/master[27664]: /etc/postfix/master.cf: line 72: using
+        backwards-compatible default setting chroot=y
+
+If this service should remain chrooted, then the system administrator should
+make the backwards-compatible setting "chroot = y" permanent in master.cf. For
+example, to update the chroot setting for the "smtp inet" service:
+
+    # ppoossttccoonnff --FF ssmmttpp//iinneett//cchhrroooott==yy
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg ssmmttppdd__rreellaayy__rreessttrriiccttiioonnss == ((eemmppttyy))
+
+The smtpd_relay_restrictions feature was introduced with Postfix version 2.10,
+as a safety mechanism for configuration errors in smtpd_recipient_restrictions
+that could make Postfix an open relay.
+
+The smtpd_relay_restrictions implicit default setting forbids mail to remote
+destinations from clients that don't match permit_mynetworks or
+permit_sasl_authenticated. This could result in unexpected 'Relay access
+denied' errors after Postfix is updated from an older Postfix version. The
+backwards-compatibility safety net is designed to prevent such surprises.
+
+When the compatibility_level less than 1, and the smtpd_relay_restrictions
+parameter is left unspecified at its implicit default setting, Postfix may log
+the following message:
+
+    postfix/smtpd[38463]: using backwards-compatible default setting
+        "smtpd_relay_restrictions = (empty)" to avoid "Relay access
+        denied" error for recipient "user@example.com" from client
+        "host.example.net[10.0.0.2]"
+
+If this request should not be blocked, then the system administrator should
+make the backwards-compatible setting "smtpd_relay_restrictions=" (i.e. empty)
+permanent in main.cf:
+
+    # ppoossttccoonnff ssmmttppdd__rreellaayy__rreessttrriiccttiioonnss==
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg ssmmttppuuttff88__eennaabbllee==nnoo
+
+The smtputf8_enable default value has changed from "no" to "yes". With the new
+"yes" setting, the Postfix SMTP server rejects non-ASCII addresses from clients
+that don't request SMTPUTF8 support, after Postfix is updated from an older
+version. The backwards-compatibility safety net is designed to prevent such
+surprises.
+
+As long as the smtputf8_enable parameter is left unspecified at its implicit
+default value, and the compatibility_level setting is less than 1, Postfix logs
+a warning each time an SMTP command uses a non-ASCII address localpart without
+requesting SMTPUTF8 support:
+
+    postfix/smtpd[27560]: using backwards-compatible default setting
+        smtputf8_enable=no to accept non-ASCII sender address
+        "??@example.org" from localhost[127.0.0.1]
+
+    postfix/smtpd[27560]: using backwards-compatible default setting
+        smtputf8_enable=no to accept non-ASCII recipient address
+        "??@example.com" from localhost[127.0.0.1]
+
+If the address should not be rejected, and the client cannot be updated to use
+SMTPUTF8, then the system administrator should make the backwards-compatible
+setting "smtputf8_enable = no" permanent in main.cf:
+
+    # ppoossttccoonnff ssmmttppuuttff88__eennaabbllee==nnoo
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg mmyynneettwwoorrkkss__ssttyyllee==ssuubbnneett
+
+The mynetworks_style default value has changed from "subnet" to "host". This
+parameter is used to implement the "permit_mynetworks" feature. The change
+could cause unexpected 'access denied' errors after Postfix is updated from an
+older version. The backwards-compatibility safety net is designed to prevent
+such surprises.
+
+As long as the mynetworks and mynetworks_style parameters are left unspecified
+at their implicit default values, and the compatibility_level setting is less
+than 2, the Postfix SMTP server may log one of the following messages:
+
+    postfix/smtpd[17375]: using backwards-compatible default setting
+        mynetworks_style=subnet to permit request from client
+        "foo.example.com[10.1.1.1]"
+
+    postfix/postscreen[24982]: using backwards-compatible default
+        setting mynetworks_style=subnet to permit request from client
+        "10.1.1.1"
+
+If the client request should not be rejected, then the system administrator
+should make the backwards-compatible setting "mynetworks_style = subnet"
+permanent in main.cf:
+
+    # ppoossttccoonnff mmyynneettwwoorrkkss__ssttyyllee==ssuubbnneett
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg rreellaayy__ddoommaaiinnss==$$mmyyddeessttiinnaattiioonn
+
+The relay_domains default value has changed from "$mydestination" to the empty
+value. This could result in unexpected 'Relay access denied' errors or ETRN
+errors after Postfix is updated from an older version. The backwards-
+compatibility safety net is designed to prevent such surprises.
+
+As long as the relay_domains parameter is left unspecified at its implicit
+default value, and the compatibility_level setting is less than 2, Postfix may
+log one of the following messages.
+
+  * Messages about accepting mail for a remote domain:
+
+        postfix/smtpd[19052]: using backwards-compatible default setting
+            relay_domains=$mydestination to accept mail for domain
+            "foo.example.com"
+
+        postfix/smtpd[19052]: using backwards-compatible default setting
+            relay_domains=$mydestination to accept mail for address
+            "user@foo.example.com"
+
+  * Messages about providing ETRN service for a remote domain:
+
+        postfix/smtpd[19138]: using backwards-compatible default setting
+            relay_domains=$mydestination to flush mail for domain
+            "bar.example.com"
+
+        postfix/smtp[13945]: using backwards-compatible default setting
+            relay_domains=$mydestination to update fast-flush logfile for
+            domain "bar.example.com"
+
+If Postfix should continue to accept mail for that domain or continue to
+provide ETRN service for that domain, then the system administrator should make
+the backwards-compatible setting "relay_domains = $mydestination" permanent in
+main.cf:
+
+    # ppoossttccoonnff ''rreellaayy__ddoommaaiinnss==$$mmyyddeessttiinnaattiioonn''
+    # ppoossttffiixx rreellooaadd
+
+Note: quotes are required as indicated above.
+
+Instead of $mydestination, it may be better to specify an explicit list of
+domain names.
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg ssmmttppdd__ttllss__ffiinnggeerrpprriinntt__ddiiggeesstt==mmdd55
+
+The smtpd_tls_fingerprint_digest default value has changed from "md5" to
+"sha256". With the new "sha256" setting, the Postfix SMTP server avoids using
+the deprecated "md5" algorithm and computes a more secure digest of the client
+certificate.
+
+If you're using the default "md5" setting, or even an explicit "sha1" (also
+deprecated) setting, you should consider switching to "sha256". This will
+require updating any associated lookup table keys with the "sha256" digests of
+the expected client certificate or public key.
+
+As long as the smtpd_tls_fingerprint_digest parameter is left unspecified at
+its implicit default value, and the compatibility_level setting is less than
+3.6, Postfix logs a warning each time a client certificate or public key
+fingerprint is (potentially) used for access control:
+
+    postfix/smtpd[27560]: using backwards-compatible default setting
+        smtpd_tls_fingerprint_digest=md5 to compute certificate fingerprints
+
+Since any client certificate fingerprints are passed in policy service lookups,
+and Postfix doesn't know whether the fingerprint will be used, the warning may
+also be logged when policy lookups are performed for connections that used a
+client certificate, even if the policy service does not in fact examine the
+client certificate. To reduce the noise somewhat, such warnings are issued at
+most once per smtpd(8) process instance.
+
+If you prefer to stick with "md5", you can suppress the warnings by making that
+setting explicit. After addressing any other compatibility warnings, you can
+update your compatibility level.
+
+    # ppoossttccoonnff ssmmttppdd__ttllss__ffiinnggeerrpprriinntt__ddiiggeesstt==mmdd55
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg ssmmttpp__ttllss__ffiinnggeerrpprriinntt__ddiiggeesstt==mmdd55
+
+The smtp_tls_fingerprint_digest and lmtp_tls_fingerprint_digest default values
+have changed from "md5" to "sha256". With the new "sha256" setting, the Postfix
+SMTP and LMTP client avoids using the deprecated "md5" algorithm and computes a
+more secure digest of the server certificate.
+
+If you're using the default "md5" setting, or even an explicit "sha1" (also
+deprecated) setting, you should consider switching to "sha256". This will
+require updating any "fingerprint" security level policies in the TLS policy
+table to specify matching "sha256" digests of the expected server certificates
+or public keys.
+
+As long as the smtp_tls_fingerprint_digest (or LMTP equivalent) parameter is
+left unspecified at its implicit default value, and the compatibility_level
+setting is less than 3.6, Postfix logs a warning each time the "fingerprint"
+security level is used to specify matching "md5" digests of trusted server
+certificates or public keys:
+
+    postfix/smtp[27560]: using backwards-compatible default setting
+        smtp_tls_fingerprint_digest=md5 to compute certificate fingerprints
+
+If you prefer to stick with "md5", you can suppress the warnings by making that
+setting explicit. After addressing any other compatibility warnings, you can
+update your compatibility level.
+
+    # ppoossttccoonnff ''ssmmttpp__ttllss__ffiinnggeerrpprriinntt__ddiiggeesstt == mmdd55'' \\
+        ''llmmttpp__ttllss__ffiinnggeerrpprriinntt__ddiiggeesstt == mmdd55''
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg
+ssmmttppdd__rreellaayy__bbeeffoorree__rreecciippiieenntt__rreessttrriiccttiioonnss==nnoo
+
+The smtpd_relay_before_recipient_restrictions feature was introduced in Postfix
+version 3.6, to evaluate smtpd_relay_restrictions before
+smtpd_recipient_restrictions. Historically, smtpd_relay_restrictions was
+evaluated after smtpd_recipient_restrictions, contradicting documented
+behavior.
+
+    Background: smtpd_relay_restrictions is primarily designed to enforce a
+    mail relaying policy, while smtpd_recipient_restrictions is primarily
+    designed to enforce spam blocking policy. Both are evaluated while replying
+    to the RCPT TO command, and both support the same features.
+
+To maintain compatibility with earlier versions, Postfix will keep evaluating
+smtpd_recipient_restrictions before smtpd_relay_restrictions, as long as the
+compatibility_level is less than 3.6, and the
+smtpd_relay_before_recipient_restrictions parameter is left unspecified at its
+implicit default setting. As a reminder, Postfix may log the following message:
+
+    postfix/smtpd[54696]: using backwards-compatible default setting
+        smtpd_relay_before_recipient_restrictions=no to reject recipient
+        "user@example.com" from client "host.example.net[10.0.0.2]"
+
+If Postfix should keep evaluating smtpd_recipient_restrictions before
+smtpd_relay_restrictions, then the system administrator should make the
+backwards-compatible setting "smtpd_relay_before_recipient_restrictions=no"
+permanent in main.cf:
+
+    #  ppoossttccoonnff ssmmttppdd__rreellaayy__bbeeffoorree__rreecciippiieenntt__rreessttrriiccttiioonnss==nnoo
+    #  ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg rreessppeeccttffuull__llooggggiinngg==nnoo
+
+Postfix version 3.6 deprecates configuration parameter names and logging that
+suggest white is better than black. Instead it prefers 'allowlist, 'denylist',
+and variations of those words. While the renamed configuration parameters have
+backwards-compatible default values, the changes in logging could affect
+logfile analysis tools.
+
+To avoid breaking existing logfile analysis tools, Postfix will keep logging
+the deprecated form, as long as the respectful_logging parameter is left
+unspecified at its implicit default value, and the compatibility_level setting
+is less than 3.6. As a reminder, Postfix may log the following when a remote
+SMTP client is allowlisted or denylisted:
+
+    postfix/postscreen[22642]: Using backwards-compatible default setting
+        respectful_logging=no for client [address]:port
+
+If Postfix should keep logging the deprecated form, then the system
+administrator should make the backwards-compatible setting "respectful_logging
+= no" permanent in main.cf.
+
+    # ppoossttccoonnff ""rreessppeeccttffuull__llooggggiinngg == nnoo""
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg
+ssmmttpp__ttllssrrpptt__sskkiipp__rreeuusseedd__hhaannddsshhaakkeess==yyeess
+
+Postfix version 3.11 changes the default value for
+smtp_tlsrpt_skip_reused_handshakes from "yes" to "no". The backwards-
+compatibility safety net is designed to prevent an unexpected change in
+reporting behavior when Postfix is updated from an older version.
+
+As long as the smtp_tlsrpt_skip_reused_handshakes parameter is left unspecified
+at its implicit default value, and the compatibility_level setting is less than
+3.11, Postfix will log a reminder that it is using the backwards-compatible
+default:
+
+    postfix/smtp[388157] using backwards-compatible default setting
+        smtp_tlsrpt_skip_reused_handshakes=yes
+
+To keep the old default setting, the system administrator should make the
+backwards-compatible setting "smtp_tlsrpt_skip_reused_handshakes = yes"
+permanent in main.cf:
+
+    # ppoossttccoonnff ssmmttpp__ttllssrrpptt__sskkiipp__rreeuusseedd__hhaannddsshhaakkeess==yyeess
+    # ppoossttffiixx rreellooaadd
+
+UUssiinngg bbaacckkwwaarrddss--ccoommppaattiibbllee ddeeffaauulltt sseettttiinngg xxxxxx__sseeccuurriittyy__lleevveell==((eemmppttyy))
+
+Postfix version 3.11 changes the default value for client TLS security levels
+from "empty" to "yes". The backwards-compatibility safety net is designed to
+prevent an unexpected change in mail sending behavior when Postfix is updated
+from an older version.
+
+There is no equivalent change for Postfix server TLS security levels, because
+changing the level alone is not sufficient. Server-side TLS requires that at
+least one private key and one public-key certificate chain are configured.
+
+As long as a TLS security level parameter is left unspecified at its implicit
+default value, and the compatibility_level setting is less than 3.11, Postfix
+will log one of the following reminders that it is using the backwards-
+compatible default:
+
+    postfix/smtp[...] using backwards-compatible default setting
+        smtp_tls_security_level=(empty)
+
+    postfix/tlsproxy[...] using backwards-compatible default setting
+        tlsproxy_client_security_level=(empty)
+
+To keep the old default setting, the system administrator should make the
+backwards-compatible empty setting permanent in main.cf:
+
+    # ppoossttccoonnff xxxxxx__sseeccuurriittyy__lleevveell==
+    # ppoossttffiixx rreellooaadd
+
+where xxx is taken from the above compatibility message.
+
+TTuurrnniinngg ooffff tthhee bbaacckkwwaarrddss--ccoommppaattiibbiilliittyy ssaaffeettyy nneett
+
+Backwards compatibility is turned off by updating the compatibility_level
+setting in main.cf.
+
+    # ppoossttccoonnff ccoommppaattiibbiilliittyy__lleevveell==NN
+    # ppoossttffiixx rreellooaadd
+
+For N specify the number that is logged in your postfix(1) warning message:
+
+    warning: To disable backwards compatibility use "postconf
+    compatibility_level=N" and "postfix reload"
+
+Sites that don't care about backwards compatibility may set
+"compatibility_level = 9999" at their own risk.
+
+Starting with Postfix version 3.6, the compatibility level in the above warning
+message is the Postfix version that introduced the last incompatible change.
+The level is formatted as major.minor.patch, where patch is usually omitted and
+defaults to zero. Earlier compatibility levels are 0, 1 and 2.
+
+NOTE: Postfix 3.6 also introduces support for the "<level", "<=level", and
+other operators to compare compatibility levels. With the standard operators
+"<", "<=", etc., compatibility level "3.10" would be smaller than "3.9" which
+is undesirable.
+

postfix/html/lmtp.8.html

@@ -174,7 +174,7 @@ SMTP(8)                                                                SMTP(8)
        <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a> (Internationalized SMTP)
        <a href="https://tools.ietf.org/html/rfc6533">RFC 6533</a> (Internationalized Delivery Status Notifications)
        <a href="https://tools.ietf.org/html/rfc7672">RFC 7672</a> (SMTP security via opportunistic DANE TLS)
-       <a href="https://tools.ietf.org/html/rfc8689">RFC 8689</a> (TLS-Required message header)
+       <a href="https://tools.ietf.org/html/rfc8689">RFC 8689</a> (SMTP REQUIRETLS extension)
 
 <b><a name="diagnostics">DIAGNOSTICS</a></b>
        Problems  and  transactions  are  logged  to <b>syslogd</b>(8) or <a href="postlogd.8.html"><b>postlogd</b>(8)</a>.
@@ -507,7 +507,7 @@ SMTP(8)                                                                SMTP(8)
               The delimiter between username and password in  sasl_passwd_maps
               lookup results.
 
-<b><a name="starttls_support_controls">STARTTLS SUPPORT CONTROLS</a></b>
+<b><a name="tls_support_controls">TLS SUPPORT CONTROLS</a></b>
        Detailed  information  about STARTTLS configuration may be found in the
        <a href="TLS_README.html">TLS_README</a> document.
 
@@ -766,41 +766,52 @@ SMTP(8)                                                                SMTP(8)
               Enable  support  for  the  "TLS-Required:  no"  message  header,
               defined in <a href="https://tools.ietf.org/html/rfc8689">RFC 8689</a>.
 
-<b><a name="obsolete_starttls_controls">OBSOLETE STARTTLS CONTROLS</a></b>
+       <b><a href="postconf.5.html#requiretls_enable">requiretls_enable</a> (yes)</b>
-       The following configuration parameters  exist  for  compatibility  with
+              Enable support for the ESMTP verb "REQUIRETLS", defined  in  <a href="https://tools.ietf.org/html/rfc8689">RFC</a>
-       Postfix  versions  before  2.3.  Support for these will be removed in a
+              <a href="https://tools.ietf.org/html/rfc8689">8689</a>.
+
+       <b><a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a> (empty)</b>
+              An  optional  list  of  next-hop  destinations  that the Postfix
+              SMTP/LMTP client will enforce REQUIRETLS for, when a message was
+              received  with  the  REQUIRETLS option: the next-hop server must
+              offer a matching TLS server certificate,  and  the  server  must
+              announce REQUIRETLS support).
+
+<b><a name="obsolete_tls_controls">OBSOLETE TLS CONTROLS</a></b>
+       The  following  configuration  parameters  exist for compatibility with
+       Postfix versions before 2.3. Support for these will  be  removed  in  a
        future release.
 
        <b><a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> (no)</b>
-              Opportunistic mode: use TLS when a remote SMTP server  announces
+              Opportunistic  mode: use TLS when a remote SMTP server announces
               STARTTLS support, otherwise send the mail in the clear.
 
        <b><a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> (no)</b>
-              Enforcement  mode:  require  that  remote  SMTP  servers use TLS
+              Enforcement mode: require  that  remote  SMTP  servers  use  TLS
               encryption, and never send mail in the clear.
 
        <b><a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> (yes)</b>
-              With mandatory TLS encryption,  require  that  the  remote  SMTP
+              With  mandatory  TLS  encryption,  require  that the remote SMTP
-              server  hostname  matches  the  information  in  the remote SMTP
+              server hostname matches  the  information  in  the  remote  SMTP
               server certificate.
 
        <b><a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> (empty)</b>
-              Optional lookup tables with the Postfix SMTP  client  TLS  usage
+              Optional  lookup  tables  with the Postfix SMTP client TLS usage
-              policy  by  next-hop destination and by remote SMTP server host-
+              policy by next-hop destination and by remote SMTP  server  host-
               name.
 
        <b><a href="postconf.5.html#smtp_tls_cipherlist">smtp_tls_cipherlist</a> (empty)</b>
-              Obsolete Postfix &lt; 2.3 control for the Postfix SMTP  client  TLS
+              Obsolete  Postfix  &lt; 2.3 control for the Postfix SMTP client TLS
               cipher list.
 
 <b><a name="resource_and_rate_controls">RESOURCE AND RATE CONTROLS</a></b>
        <b><a href="postconf.5.html#smtp_connect_timeout">smtp_connect_timeout</a> (30s)</b>
-              The  Postfix SMTP client time limit for completing a TCP connec-
+              The Postfix SMTP client time limit for completing a TCP  connec-
               tion, or zero (use the operating system built-in time limit).
 
        <b><a href="postconf.5.html#smtp_helo_timeout">smtp_helo_timeout</a> (300s)</b>
-              The Postfix SMTP client time limit for sending the HELO or  EHLO
+              The  Postfix SMTP client time limit for sending the HELO or EHLO
-              command,  and  for  receiving  the  initial  remote  SMTP server
+              command, and  for  receiving  the  initial  remote  SMTP  server
               response.
 
        <b><a href="postconf.5.html#lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> (300s)</b>
@@ -812,19 +823,19 @@ SMTP(8)                                                                SMTP(8)
               mand, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_mail_timeout">smtp_mail_timeout</a> (300s)</b>
-              The Postfix SMTP client time limit for  sending  the  MAIL  FROM
+              The  Postfix  SMTP  client  time limit for sending the MAIL FROM
               command, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_rcpt_timeout">smtp_rcpt_timeout</a> (300s)</b>
-              The  Postfix SMTP client time limit for sending the SMTP RCPT TO
+              The Postfix SMTP client time limit for sending the SMTP RCPT  TO
               command, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_data_init_timeout">smtp_data_init_timeout</a> (120s)</b>
-              The Postfix SMTP client time limit for  sending  the  SMTP  DATA
+              The  Postfix  SMTP  client  time limit for sending the SMTP DATA
               command, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> (180s)</b>
-              The  Postfix SMTP client time limit for sending the SMTP message
+              The Postfix SMTP client time limit for sending the SMTP  message
               content.
 
        <b><a href="postconf.5.html#smtp_data_done_timeout">smtp_data_done_timeout</a> (600s)</b>
@@ -838,13 +849,13 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 2.1 and later:
 
        <b><a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a> (5)</b>
-              The maximal number of MX (mail exchanger) IP addresses that  can
+              The  maximal number of MX (mail exchanger) IP addresses that can
-              result  from Postfix SMTP client mail exchanger lookups, or zero
+              result from Postfix SMTP client mail exchanger lookups, or  zero
               (no limit).
 
        <b><a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> (2)</b>
-              The maximal number of SMTP sessions per delivery request  before
+              The  maximal number of SMTP sessions per delivery request before
-              the  Postfix  SMTP  client  gives  up or delivers to a fall-back
+              the Postfix SMTP client gives up  or  delivers  to  a  fall-back
               <a href="postconf.5.html#relayhost">relay host</a>, or zero (no limit).
 
        <b><a href="postconf.5.html#smtp_rset_timeout">smtp_rset_timeout</a> (20s)</b>
@@ -854,17 +865,17 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 2.2 and earlier:
 
        <b><a href="postconf.5.html#lmtp_cache_connection">lmtp_cache_connection</a> (yes)</b>
-              Keep  Postfix  LMTP  client connections open for up to $<a href="postconf.5.html#max_idle">max_idle</a>
+              Keep Postfix LMTP client connections open for  up  to  $<a href="postconf.5.html#max_idle">max_idle</a>
               seconds.
 
        Available in Postfix version 2.2 and later:
 
        <b><a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> (empty)</b>
-              Permanently enable SMTP connection  caching  for  the  specified
+              Permanently  enable  SMTP  connection  caching for the specified
               destinations.
 
        <b><a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> (yes)</b>
-              Temporarily  enable  SMTP connection caching while a destination
+              Temporarily enable SMTP connection caching while  a  destination
               has a high volume of mail in the <a href="QSHAPE_README.html#active_queue">active queue</a>.
 
        <b><a href="postconf.5.html#smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a> (300s)</b>
@@ -878,23 +889,23 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 2.3 and later:
 
        <b><a href="postconf.5.html#connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> (5s)</b>
-              Time limit for connection cache connect, send or receive  opera-
+              Time  limit for connection cache connect, send or receive opera-
               tions.
 
        Available in Postfix version 2.9 - 3.6:
 
        <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b>
-              Change  the  behavior  of the smtp_*_timeout time limits, from a
+              Change the behavior of the smtp_*_timeout time  limits,  from  a
-              time limit per read or write system call, to  a  time  limit  to
+              time  limit  per  read  or write system call, to a time limit to
-              send  or  receive  a complete record (an SMTP command line, SMTP
+              send or receive a complete record (an SMTP  command  line,  SMTP
-              response line, SMTP message content line, or TLS  protocol  mes-
+              response  line,  SMTP message content line, or TLS protocol mes-
               sage).
 
        Available in Postfix version 2.11 and later:
 
        <b><a href="postconf.5.html#smtp_connection_reuse_count_limit">smtp_connection_reuse_count_limit</a> (0)</b>
-              When  SMTP  connection  caching  is enabled, the number of times
+              When SMTP connection caching is enabled,  the  number  of  times
-              that an SMTP session may be reused before it is closed, or  zero
+              that  an SMTP session may be reused before it is closed, or zero
               (no limit).
 
        Available in Postfix version 3.4 and later:
@@ -905,13 +916,13 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 3.7 and later:
 
        <b><a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a> (no)</b>
-              Change  the  behavior  of the smtp_*_timeout time limits, from a
+              Change the behavior of the smtp_*_timeout time  limits,  from  a
-              time limit per plaintext or TLS read or write call,  to  a  com-
+              time  limit  per  plaintext or TLS read or write call, to a com-
-              bined  time  limit  for  sending a complete SMTP request and for
+              bined time limit for sending a complete  SMTP  request  and  for
               receiving a complete SMTP response.
 
        <b><a href="postconf.5.html#smtp_min_data_rate">smtp_min_data_rate</a> (500)</b>
-              The minimum plaintext data transfer  rate  in  bytes/second  for
+              The  minimum  plaintext  data  transfer rate in bytes/second for
               DATA    requests,    when    deadlines    are    enabled    with
               <a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a>.
 
@@ -919,54 +930,54 @@ SMTP(8)                                                                SMTP(8)
 
        <b><a href="postconf.5.html#transport_destination_concurrency_limit">transport_destination_concurrency_limit</a>   ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concur</a>-</b>
        <b><a href="postconf.5.html#default_destination_concurrency_limit">rency_limit</a>)</b>
-              A transport-specific override for  the  <a href="postconf.5.html#default_destination_concurrency_limit">default_destination_con</a>-
+              A  transport-specific  override for the <a href="postconf.5.html#default_destination_concurrency_limit">default_destination_con</a>-
               <a href="postconf.5.html#default_destination_concurrency_limit">currency_limit</a> parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a>
               name of the message delivery transport.
 
        <b><a href="postconf.5.html#transport_destination_recipient_limit">transport_destination_recipient_limit</a>     ($<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipi</a>-</b>
        <b><a href="postconf.5.html#default_destination_recipient_limit">ent_limit</a>)</b>
               A transport-specific override for the <a href="postconf.5.html#default_destination_recipient_limit">default_destination_recip</a>-
-              <a href="postconf.5.html#default_destination_recipient_limit">ient_limit</a>  parameter  value,  where  <i>transport</i> is the <a href="master.5.html">master.cf</a>
+              <a href="postconf.5.html#default_destination_recipient_limit">ient_limit</a> parameter value, where  <i>transport</i>  is  the  <a href="master.5.html">master.cf</a>
               name of the message delivery transport.
 
 <b><a name="smtputf8_controls">SMTPUTF8 CONTROLS</a></b>
        Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
 
        <b><a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a> (yes)</b>
-              Enable preliminary SMTPUTF8 support for the protocols  described
+              Enable  preliminary SMTPUTF8 support for the protocols described
               in <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a>, <a href="https://tools.ietf.org/html/rfc6532">RFC 6532</a>, and <a href="https://tools.ietf.org/html/rfc6533">RFC 6533</a>.
 
        <b><a href="postconf.5.html#smtputf8_autodetect_classes">smtputf8_autodetect_classes</a> (sendmail, verify)</b>
-              Detect  that  a message requires SMTPUTF8 support for the speci-
+              Detect that a message requires SMTPUTF8 support for  the  speci-
               fied mail origin classes.
 
        Available in Postfix version 3.2 and later:
 
        <b><a href="postconf.5.html#enable_idna2003_compatibility">enable_idna2003_compatibility</a> (no)</b>
-              Enable  'transitional'  compatibility   between   IDNA2003   and
+              Enable   'transitional'   compatibility   between  IDNA2003  and
-              IDNA2008,  when  converting UTF-8 domain names to/from the ASCII
+              IDNA2008, when converting UTF-8 domain names to/from  the  ASCII
               form that is used for DNS lookups.
 
 <b><a name="trouble_shooting_controls">TROUBLE SHOOTING CONTROLS</a></b>
        <b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
-              The increment in verbose logging level when a  nexthop  destina-
+              The  increment  in verbose logging level when a nexthop destina-
-              tion,  remote client or server name or network address matches a
+              tion, remote client or server name or network address matches  a
               pattern given with the <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
 
        <b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
-              Optional list of nexthop destination, remote  client  or  server
+              Optional  list  of  nexthop destination, remote client or server
-              name  or  network  address  patterns that, if matched, cause the
+              name or network address patterns that,  if  matched,  cause  the
-              verbose logging level to increase by  the  amount  specified  in
+              verbose  logging  level  to  increase by the amount specified in
               $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
 
        <b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
-              The  recipient  of  postmaster notifications about mail delivery
+              The recipient of postmaster notifications  about  mail  delivery
               problems that are caused by policy, resource, software or proto-
               col errors.
 
        <b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b>
-              What   categories  of  Postfix-generated  mail  are  subject  to
+              What  categories  of  Postfix-generated  mail  are  subject   to
-              before-queue   content    inspection    by    <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>,
+              before-queue    content    inspection    by   <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>,
               <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>.
 
        <b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b>
@@ -974,46 +985,46 @@ SMTP(8)                                                                SMTP(8)
 
 <b><a name="miscellaneous_controls">MISCELLANEOUS CONTROLS</a></b>
        <b><a href="postconf.5.html#best_mx_transport">best_mx_transport</a> (empty)</b>
-              Where  the  Postfix  SMTP  client  should  deliver  mail when it
+              Where the Postfix  SMTP  client  should  deliver  mail  when  it
               detects a "mail loops back to myself" error condition.
 
        <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
-              The default location of the Postfix <a href="postconf.5.html">main.cf</a> and  <a href="master.5.html">master.cf</a>  con-
+              The  default  location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
               figuration files.
 
        <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
-              How  much  time  a  Postfix  daemon process may take to handle a
+              How much time a Postfix daemon process  may  take  to  handle  a
               request before it is terminated by a built-in watchdog timer.
 
        <b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b>
-              The maximal number of digits after the decimal point  when  log-
+              The  maximal  number of digits after the decimal point when log-
               ging delay values.
 
        <b><a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a> (no)</b>
               Disable DNS lookups in the Postfix SMTP and LMTP clients.
 
        <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
-              The  local  network  interface  addresses  that this mail system
+              The local network interface  addresses  that  this  mail  system
               receives mail on.
 
        <b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (see 'postconf -d' output)</b>
-              The Internet protocols Postfix will attempt to use  when  making
+              The  Internet  protocols Postfix will attempt to use when making
               or accepting connections.
 
        <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
-              The  time  limit  for  sending  or receiving information over an
+              The time limit for sending  or  receiving  information  over  an
               internal communication channel.
 
        <b><a href="postconf.5.html#lmtp_assume_final">lmtp_assume_final</a> (no)</b>
-              When a remote LMTP server announces no DSN support, assume  that
+              When  a remote LMTP server announces no DSN support, assume that
-              the  server performs final delivery, and send "delivered" deliv-
+              the server performs final delivery, and send "delivered"  deliv-
               ery status notifications instead of "relayed".
 
        <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a> (24)</b>
               The default TCP port that the Postfix LMTP client connects to.
 
        <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
-              The maximum amount of time that an idle Postfix  daemon  process
+              The  maximum  amount of time that an idle Postfix daemon process
               waits for an incoming connection before terminating voluntarily.
 
        <b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
@@ -1027,21 +1038,21 @@ SMTP(8)                                                                SMTP(8)
               The process name of a Postfix command or daemon process.
 
        <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
-              The  remote  network  interface  addresses that this mail system
+              The remote network interface addresses  that  this  mail  system
-              receives mail on by way of a proxy or network  address  transla-
+              receives  mail  on by way of a proxy or network address transla-
               tion unit.
 
        <b><a href="postconf.5.html#smtp_address_preference">smtp_address_preference</a> (any)</b>
               The address type ("ipv6", "ipv4" or "any") that the Postfix SMTP
-              client will try first, when a  destination  has  IPv6  and  IPv4
+              client  will  try  first,  when  a destination has IPv6 and IPv4
               addresses with equal MX preference.
 
        <b><a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> (empty)</b>
-              An  optional  numerical  network  address  that the Postfix SMTP
+              An optional numerical network  address  that  the  Postfix  SMTP
               client should bind to when making an IPv4 connection.
 
        <b><a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> (empty)</b>
-              An optional numerical network  address  that  the  Postfix  SMTP
+              An  optional  numerical  network  address  that the Postfix SMTP
               client should bind to when making an IPv6 connection.
 
        <b><a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
@@ -1061,7 +1072,7 @@ SMTP(8)                                                                SMTP(8)
               The syslog facility of Postfix logging.
 
        <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
-              A prefix that  is  prepended  to  the  process  name  in  syslog
+              A  prefix  that  is  prepended  to  the  process  name in syslog
               records, so that, for example, "smtpd" becomes "prefix/smtpd".
 
        Available with Postfix 2.2 and earlier:
@@ -1073,14 +1084,14 @@ SMTP(8)                                                                SMTP(8)
        Available with Postfix 2.3 and later:
 
        <b><a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a> ($<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b>
-              Optional list of relay destinations that will be  used  when  an
+              Optional  list  of  relay destinations that will be used when an
-              SMTP  destination  is not found, or when delivery fails due to a
+              SMTP destination is not found, or when delivery fails due  to  a
               non-permanent error.
 
        Available with Postfix 3.0 and later:
 
        <b><a href="postconf.5.html#smtp_address_verify_target">smtp_address_verify_target</a> (rcpt)</b>
-              In the context of email address verification, the SMTP  protocol
+              In  the context of email address verification, the SMTP protocol
               stage that determines whether an email address is deliverable.
 
        Available with Postfix 3.1 and later:
@@ -1102,7 +1113,7 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix 3.7 and later:
 
        <b><a href="postconf.5.html#smtp_bind_address_enforce">smtp_bind_address_enforce</a> (no)</b>
-              Defer delivery when the Postfix SMTP  client  cannot  apply  the
+              Defer  delivery  when  the  Postfix SMTP client cannot apply the
               <a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> or <a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> setting.
 
 <b><a name="see_also">SEE ALSO</a></b>

postfix/html/mailq.1.html

@@ -168,12 +168,32 @@ SENDMAIL(1)                                                        SENDMAIL(1)
               Delivery   status   notification   control.   Specify  either  a
               comma-separated list with one or more of <b>failure</b> (send notifica-
               tion  when delivery fails), <b>delay</b> (send notification when deliv-
-              ery is delayed), or <b>success</b> (send notification when the  message
+              ery is delayed), or <b>success</b> (send notification after the message
               is delivered); or specify <b>never</b> (don't send any notifications at
               all).
 
               This feature is available in Postfix 2.3 and later.
 
+       <b>-O requiretls</b>
+              When delivering a message to an SMTP or LMTP server, the connec-
+              tion  must  use  TLS with a verified server certificate, and the
+              server must support REQUIRETLS. Try multiple servers  if  possi-
+              ble, and return the message as undeliverable when these require-
+              ments were not satisfied with  any  of  the  servers  that  were
+              tried. The "requiretls" option value is case-insensitive.
+
+              This feature is available in Postfix 3.10 and later.
+
+       <b>-O smtputf8</b>
+              When  delivering a message to an SMTP or LMTP server, the server
+              must support SMTPUTF8. Try multiple  servers  if  possible,  and
+              return  the  message as undeliverable when a message contains an
+              UTF8 envelope address or message header, but  SMTPUTF8  was  not
+              supported  by any of the servers that were tried. The "smtputf8"
+              option value is case-insensitive.
+
+              This feature is available in Postfix 3.10 and later.
+
        <b>-n</b> (ignored)
               Backwards compatibility.
 
@@ -483,6 +503,12 @@ SENDMAIL(1)                                                        SENDMAIL(1)
               the  default  Postfix  instance,  and that are started, stopped,
               etc., together with the default Postfix instance.
 
+       Postfix 3.10 and later:
+
+       <b><a href="postconf.5.html#requiretls_enable">requiretls_enable</a> (yes)</b>
+              Enable support for the ESMTP verb "REQUIRETLS", defined  in  <a href="https://tools.ietf.org/html/rfc8689">RFC</a>
+              <a href="https://tools.ietf.org/html/rfc8689">8689</a>.
+
 <b><a name="files">FILES</a></b>
        /var/spool/postfix, mail queue
        /etc/postfix, configuration files
@@ -501,7 +527,7 @@ SENDMAIL(1)                                                        SENDMAIL(1)
        syslogd(8), system logging
 
 <b><a name="readme_files">README_FILES</a></b>
-       Use "<b>postconf <a href="postconf.5.html#readme_directory">readme_directory</a></b>" or "<b>postconf <a href="postconf.5.html#html_directory">html_directory</a></b>" to  locate
+       Use  "<b>postconf <a href="postconf.5.html#readme_directory">readme_directory</a></b>" or "<b>postconf <a href="postconf.5.html#html_directory">html_directory</a></b>" to locate
        this information.
        <a href="DEBUG_README.html">DEBUG_README</a>, Postfix debugging howto
        <a href="ETRN_README.html">ETRN_README</a>, Postfix ETRN howto

postfix/html/newaliases.1.html

@@ -168,12 +168,32 @@ SENDMAIL(1)                                                        SENDMAIL(1)
               Delivery   status   notification   control.   Specify  either  a
               comma-separated list with one or more of <b>failure</b> (send notifica-
               tion  when delivery fails), <b>delay</b> (send notification when deliv-
-              ery is delayed), or <b>success</b> (send notification when the  message
+              ery is delayed), or <b>success</b> (send notification after the message
               is delivered); or specify <b>never</b> (don't send any notifications at
               all).
 
               This feature is available in Postfix 2.3 and later.
 
+       <b>-O requiretls</b>
+              When delivering a message to an SMTP or LMTP server, the connec-
+              tion  must  use  TLS with a verified server certificate, and the
+              server must support REQUIRETLS. Try multiple servers  if  possi-
+              ble, and return the message as undeliverable when these require-
+              ments were not satisfied with  any  of  the  servers  that  were
+              tried. The "requiretls" option value is case-insensitive.
+
+              This feature is available in Postfix 3.10 and later.
+
+       <b>-O smtputf8</b>
+              When  delivering a message to an SMTP or LMTP server, the server
+              must support SMTPUTF8. Try multiple  servers  if  possible,  and
+              return  the  message as undeliverable when a message contains an
+              UTF8 envelope address or message header, but  SMTPUTF8  was  not
+              supported  by any of the servers that were tried. The "smtputf8"
+              option value is case-insensitive.
+
+              This feature is available in Postfix 3.10 and later.
+
        <b>-n</b> (ignored)
               Backwards compatibility.
 
@@ -483,6 +503,12 @@ SENDMAIL(1)                                                        SENDMAIL(1)
               the  default  Postfix  instance,  and that are started, stopped,
               etc., together with the default Postfix instance.
 
+       Postfix 3.10 and later:
+
+       <b><a href="postconf.5.html#requiretls_enable">requiretls_enable</a> (yes)</b>
+              Enable support for the ESMTP verb "REQUIRETLS", defined  in  <a href="https://tools.ietf.org/html/rfc8689">RFC</a>
+              <a href="https://tools.ietf.org/html/rfc8689">8689</a>.
+
 <b><a name="files">FILES</a></b>
        /var/spool/postfix, mail queue
        /etc/postfix, configuration files
@@ -501,7 +527,7 @@ SENDMAIL(1)                                                        SENDMAIL(1)
        syslogd(8), system logging
 
 <b><a name="readme_files">README_FILES</a></b>
-       Use "<b>postconf <a href="postconf.5.html#readme_directory">readme_directory</a></b>" or "<b>postconf <a href="postconf.5.html#html_directory">html_directory</a></b>" to  locate
+       Use  "<b>postconf <a href="postconf.5.html#readme_directory">readme_directory</a></b>" or "<b>postconf <a href="postconf.5.html#html_directory">html_directory</a></b>" to locate
        this information.
        <a href="DEBUG_README.html">DEBUG_README</a>, Postfix debugging howto
        <a href="ETRN_README.html">ETRN_README</a>, Postfix ETRN howto

postfix/html/pipe.8.html

@@ -309,6 +309,15 @@ PIPE(8)                                                                PIPE(8)
                      This information is modified by the <b>hqu</b> flags for quoting
                      and case folding.
 
+              <b>${requiretls}</b>
+                     This  feature  should  be  used with content filters that
+                     pass filtered mail to the  Postfix  <a href="sendmail.1.html">sendmail(1)</a>  command.
+                     The  macro expands to the <a href="sendmail.1.html">sendmail(1)</a> command-line option
+                     <b>-Orequiretls</b> if the sender requested  REQUIRETLS,  other-
+                     wise it expands to <b>-Onoop</b>.
+
+                     This feature is available as of Postfix 3.10.
+
               <b>${sasl_method}</b>
                      This macro expands to the name of the SASL authentication
                      mechanism in the  AUTH  command  when  the  Postfix  SMTP

postfix/html/postconf.5.html

@@ -5041,6 +5041,17 @@ configuration parameter.  See there for details.  </p>
 <p> This feature is available in Postfix 2.11 and later.  </p>
 
 
+</DD>
+
+<DT><b><a name="lmtp_enforce_requiretls">lmtp_enforce_requiretls</a>
+(default: empty)</b></DT><DD>
+
+<p> The LMTP-specific version of the <a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a>
+configuration parameter. See there for details. </p>
+
+<p> This feature is available in Postfix &ge; 3.11. </p>
+
+
 </DD>
 
 <DT><b><a name="lmtp_enforce_tls">lmtp_enforce_tls</a>
@@ -8218,6 +8229,13 @@ you really want to match subdomains.
 <a href="postconf.5.html#smtpd_client_event_limit_exceptions">smtpd_client_event_limit_exceptions</a>
 </dd>
 
+<dt> Postfix version 3.11 and later </dt>
+
+<dd>
+<a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a>,
+<a href="postconf.5.html#lmtp_enforce_requiretls">lmtp_enforce_requiretls</a>
+</dd>
+
 </dl>
 
 
@@ -10596,6 +10614,37 @@ the mail server (IMPORTING HOME DIRECTORIES IS NOT RECOMMENDED).
 </p>
 
 
+</DD>
+
+<DT><b><a name="requiretls_enable">requiretls_enable</a>
+(default: yes)</b></DT><DD>
+
+<p> Enable support for the ESMTP verb "REQUIRETLS", defined in <a href="https://tools.ietf.org/html/rfc8689">RFC</a>
+<a href="https://tools.ietf.org/html/rfc8689">8689</a>. By issuing this verb in the "MAIL FROM" command, a sender
+specifies that a message must be delivered over TLS connections
+with a verified server certificate, to a server that announces
+"REQUIRETLS" support. This corresponds to the Postfix SMTP client
+TLS security levels "secure", "verify", "fingerprint", dane-only,
+or opportunistic "dane", with a successful certificate match. The
+Postfix SMTP client will try one or more servers, controlled with
+the <a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a> parameter, until it finds a server that
+satisfies requirements. Otherwise, Postfix returns the message as
+undeliverable. </p>
+
+<p> Notes: </p>
+
+<ul>
+
+<li> <p> REQUIRETLS enforcement is controlled with <a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a>
+or <a href="postconf.5.html#lmtp_enforce_requiretls">lmtp_enforce_requiretls</a>. </p>
+
+<li> <p> REQUIRETLS overrides "TLS-Required: no". </p>
+
+</ul>
+
+<p> This feature is available in Postfix &ge; 3.11. </p>
+
+
 </DD>
 
 <DT><b><a name="reset_owner_alias">reset_owner_alias</a>
@@ -11927,6 +11976,86 @@ RES_USE_DNSSEC and RES_USE_EDNS0 resolver options. </p>
 <p> This feature is available in Postfix 2.11 and later.  </p>
 
 
+</DD>
+
+<DT><b><a name="smtp_enforce_requiretls">smtp_enforce_requiretls</a>
+(default: empty)</b></DT><DD>
+
+<p> An optional list of next-hop destinations that the Postfix
+SMTP/LMTP client will enforce REQUIRETLS for, when a message was
+received with the REQUIRETLS option: the next-hop server must offer
+a matching TLS server certificate, and the server must announce
+REQUIRETLS support). Such a message will be returned to the sender
+if some REQUIRETLS requirement cannot be satisfied. These "hard"
+REQUIRETLS failures are logged as "REQUIRETLS failure". </p>
+
+<p> Other messages that were received with the REQUIRETLS option
+will be delivered with REQUIRETLS if possible. If not, a message
+will be delivered as if it was received without the REQUIRETLS
+option. This allows a mail sending site to discover when REQUIRETLS
+can be enforced, without disrupting email deliveries. These "soft"
+REQUIRETLS failures are logged with "REQUIRETLS Debug". </p>
+
+<p> On a perimeter MTA, it can make sense to turn off REQUIRETLS
+enforcement, or even to turn off REQUIRETLS support, when delivering
+a message to an internal destination. The internal servers may not
+support REQUIRETLS, and their connections may be secured with means
+other than DANE, STS, and the like. </p>
+
+<p> The supported syntax differs with SMTP and LMTP: </p>
+
+<ul>
+
+<li> <p> With SMTP, specify a list of next-hop domain names (without
+the ":port" or ":service" suffix), "/file/name" patterns or
+"<a href="DATABASE_README.html">type:table</a>" lookup tables, separated by commas and/or whitespace.
+Continue long lines by starting the next line with whitespace. A
+"/file/name" pattern is replaced by its contents.  A "<a href="DATABASE_README.html">type:table</a>"
+lookup table is matched when a domain appears as lookup key. Specify
+"!pattern" to exclude a domain. </p>
+
+<li> <p> With LMTP, specify list of domain names (without the "inet":
+prefix, or  ":port" or ":service" suffix), or UNIX-domain socket
+"/path/name" (without the "unix:" prefix), or "<a href="DATABASE_README.html">type:table</a>" lookup
+tables, separated by commas and/or whitespace. Continue long lines
+by starting the next line with whitespace. A "<a href="DATABASE_README.html">type:table</a>" lookup
+table is matched when a domain appears as lookup key. Specify
+"!pattern" to exclude a domain or socket path. </p>
+
+</ul>
+
+<p> Specify the form ".domain" to match any name ending in ".domain".
+To change this behavior, list "<a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a>" or
+"<a href="postconf.5.html#lmtp_enforce_requiretls">lmtp_enforce_requiretls</a>" in the <a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a>
+parameter value.  </p>
+
+<p>
+SMTP Examples:
+</p>
+
+<pre>
+# Enforce REQUIRETLS for SMTP with selected next-hop domains.
+<a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a> = example.com, foo.example
+<br>
+# Enforce REQUIRETLS for SMTP with all but a few next-hop domains.
+<a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a> = !foo.example, <a href="DATABASE_README.html#types">static</a>:all
+</pre>
+
+<p>
+LMTP examples:
+</p>
+
+<pre>
+# Don't enforce REQUIRETLS
+<a href="postconf.5.html#lmtp_enforce_requiretls">lmtp_enforce_requiretls</a> =
+<br>
+# Enforce REQUIRETLS for specific destinations.
+<a href="postconf.5.html#lmtp_enforce_requiretls">lmtp_enforce_requiretls</a> = /path/to/socket, message-store.example
+</pre>
+
+<p> This feature is available in Postfix &ge; 3.11. </p>
+
+
 </DD>
 
 <DT><b><a name="smtp_enforce_tls">smtp_enforce_tls</a>
@@ -20789,6 +20918,8 @@ If a message contains a "TLS-Required: no" header, then Postfix
 will add that header to a delivery status notification for that
 message. </p>
 
+<p> Note: REQUIRETLS overrides "TLS-Required: no". </p>
+
 <p> This feature is available in Postfix &ge; 3.10. </p>
 
 

postfix/html/relocated.5.html

@@ -5,7 +5,7 @@
 <link rel='stylesheet' type='text/css' href='postfix-doc.css'>
 <title> Postfix manual - relocated(5) </title>
 </head> <body> <pre>
-<i>RELOCATED</i>(5)                  File Formats Manual                 <i>RELOCATED</i>(5)
+RELOCATED(5)                                                      RELOCATED(5)
 
 <b><a name="name">NAME</a></b>
        relocated - Postfix relocated table format
@@ -19,25 +19,25 @@
 
        Normally, the <a href="relocated.5.html"><b>relocated</b>(5)</a> table is  specified  as  a  text  file  that
        serves as input to the <a href="postmap.1.html"><b>postmap</b>(1)</a> command.  The result, an indexed file
-       in <b>dbm</b> or <b>db</b> format, is used for fast searching by the mail system. Ex-
+       in <b>dbm</b> or <b>db</b> format, is used for fast searching  by  the  mail  system.
-       ecute  the  command  "<b>postmap /etc/postfix/relocated</b>" to rebuild an in-
+       Execute  the  command  "<b>postmap  /etc/postfix/relocated</b>"  to rebuild an
-       dexed file after changing the corresponding relocated table.
+       indexed file after changing the corresponding relocated table.
 
        When the table is provided via other means such as NIS,  LDAP  or  SQL,
        the same lookups are done as for ordinary indexed files.
 
        Alternatively,  the  table  can be provided as a regular-expression map
-       where patterns are given as regular expressions, or lookups can be  di-
+       where patterns are given as regular  expressions,  or  lookups  can  be
-       rected  to a TCP-based server. In those case, the lookups are done in a
+       directed  to a TCP-based server. In those case, the lookups are done in
-       slightly different way as described below under "REGULAR EXPRESSION TA-
+       a slightly different way as described below under  "REGULAR  EXPRESSION
-       BLES" or "TCP-BASED TABLES".
+       TABLES" or "TCP-BASED TABLES".
 
        Table lookups are case insensitive.
 
 <b><a name="case_folding">CASE FOLDING</a></b>
-       The search string is folded to lowercase before database lookup. As  of
+       The  search string is folded to lowercase before database lookup. As of
-       Postfix  2.3,  the search string is not case folded with database types
+       Postfix 2.3, the search string is not case folded with  database  types
-       such as <a href="regexp_table.5.html">regexp</a>: or <a href="pcre_table.5.html">pcre</a>: whose lookup fields can match both  upper  and
+       such  as  <a href="regexp_table.5.html">regexp</a>: or <a href="pcre_table.5.html">pcre</a>: whose lookup fields can match both upper and
        lower case.
 
 <b><a name="table_format">TABLE FORMAT</a></b>
@@ -48,29 +48,29 @@
                    <i>pattern      new</i><b>_</b><i>location</i>
 
               Where <i>new</i><b>_</b><i>location</i> specifies  contact  information  such  as  an
-              email address, or perhaps a street address or telephone number.
+              email  address, or perhaps a street address or telephone number.
 
-       <b>o</b>      Postfix  3.11  and  later  can optionally disable the hard-coded
+       <b>o</b>      Postfix 3.11 and later can  optionally  disable  the  hard-coded
-              prefix. Specify "<a href="postconf.5.html#relocated_prefix_enable">relocated_prefix_enable</a> = no" in  <a href="postconf.5.html">main.cf</a>,  and
+              prefix.  Specify  "<a href="postconf.5.html#relocated_prefix_enable">relocated_prefix_enable</a> = no" in <a href="postconf.5.html">main.cf</a>, and
-              specify  <a href="postconf.5.html#relocated_maps">relocated_maps</a> entries with your own <a href="https://tools.ietf.org/html/rfc3463">RFC 3463</a>-compliant
+              specify <a href="postconf.5.html#relocated_maps">relocated_maps</a> entries with your own <a href="https://tools.ietf.org/html/rfc3463">RFC  3463</a>-compliant
               enhanced status code and text, for example:
 
                    <i>pattern</i>      5.2.0 Mailbox is unavailable
                    <i>pattern</i>      5.2.1 Mailbox is disabled
 
-       <b>o</b>      Empty lines and whitespace-only lines are ignored, as are  lines
+       <b>o</b>      Empty  lines and whitespace-only lines are ignored, as are lines
               whose first non-whitespace character is a `#'.
 
-       <b>o</b>      A  logical  line  starts  with  non-whitespace text. A line that
+       <b>o</b>      A logical line starts with  non-whitespace  text.  A  line  that
               starts with whitespace continues a logical line.
 
 <b><a name="table_search_order">TABLE SEARCH ORDER</a></b>
-       With lookups from indexed files such as DB or DBM,  or  from  networked
+       With  lookups  from  indexed files such as DB or DBM, or from networked
-       tables  such  as  NIS,  LDAP or SQL, patterns are tried in the order as
+       tables such as NIS, LDAP or SQL, patterns are tried  in  the  order  as
        listed below:
 
        <i>user</i>@<i>domain</i>
-              Matches <i>user</i>@<i>domain</i>. This form has  precedence  over  all  other
+              Matches  <i>user</i>@<i>domain</i>.  This  form  has precedence over all other
               forms.
 
        <i>user</i>   Matches <i>user</i>@<i>site</i> when <i>site</i> is $<b><a href="postconf.5.html#myorigin">myorigin</a></b>, when <i>site</i> is listed in
@@ -83,21 +83,21 @@
 
 <b><a name="address_extension">ADDRESS EXTENSION</a></b>
        When a mail address localpart contains the optional recipient delimiter
-       (e.g.,  <i>user+foo</i>@<i>domain</i>),  the  lookup  order becomes: <i>user+foo</i>@<i>domain</i>,
+       (e.g., <i>user+foo</i>@<i>domain</i>), the  lookup  order  becomes:  <i>user+foo</i>@<i>domain</i>,
        <i>user</i>@<i>domain</i>, <i>user+foo</i>, <i>user</i>, and @<i>domain</i>.
 
 <b><a name="regular_expression_tables">REGULAR EXPRESSION TABLES</a></b>
-       This section describes how the table lookups change when the  table  is
+       This  section  describes how the table lookups change when the table is
-       given  in  the form of regular expressions or when lookups are directed
+       given in the form of regular expressions or when lookups  are  directed
-       to a TCP-based server. For a description of regular  expression  lookup
+       to  a  TCP-based server. For a description of regular expression lookup
-       table  syntax,  see <a href="regexp_table.5.html"><b>regexp_table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre_table</b>(5)</a>. For a description
+       table syntax, see <a href="regexp_table.5.html"><b>regexp_table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre_table</b>(5)</a>. For  a  description
        of the TCP client/server table lookup protocol, see <a href="tcp_table.5.html"><b>tcp_table</b>(5)</a>.  This
        feature is available in Postfix 2.5 and later.
 
-       Each pattern is a regular expression that is applied to the entire  ad-
+       Each pattern is a regular expression that  is  applied  to  the  entire
-       dress  being looked up. Thus, <i>user@domain</i> mail addresses are not broken
+       address  being looked up. Thus, <i>user@domain</i> mail addresses are not bro-
-       up into their <i>user</i> and <i>@domain</i> constituent parts, nor is <i>user+foo</i>  bro-
+       ken up into their <i>user</i> and <i>@domain</i> constituent parts, nor  is  <i>user+foo</i>
-       ken up into <i>user</i> and <i>foo</i>.
+       broken up into <i>user</i> and <i>foo</i>.
 
        Patterns  are  applied  in the order as specified in the table, until a
        pattern is found that matches the search string.
@@ -122,9 +122,9 @@
        The table format does not understand quoting conventions.
 
 <b><a name="configuration_parameters">CONFIGURATION PARAMETERS</a></b>
-       The following <a href="postconf.5.html"><b>main.cf</b></a> parameters are especially relevant.  The text be-
+       The  following  <a href="postconf.5.html"><b>main.cf</b></a>  parameters  are especially relevant.  The text
-       low provides only a parameter summary. See <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details
+       below provides only a  parameter  summary.  See  <a href="postconf.5.html"><b>postconf</b>(5)</a>  for  more
-       including examples.
+       details including examples.
 
        <b><a href="postconf.5.html#relocated_maps">relocated_maps</a> (empty)</b>
               Optional lookup tables with new contact information for users or
@@ -133,27 +133,27 @@
        Available with Postfix version 3.11 and later:
 
        <b><a href="postconf.5.html#relocated_prefix_enable">relocated_prefix_enable</a> (yes)</b>
-              Prepend  the  prefix  "<b>5.1.6  User  has  moved to</b> " to all relo-
+              Prepend the prefix "<b>5.1.6 User has  moved  to</b>  "  to  all  relo-
               cated_maps lookup results.
 
        Other parameters of interest:
 
        <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
-              The local network interface addresses that this mail system  re-
+              The  local  network  interface  addresses  that this mail system
-              ceives mail on.
+              receives mail on.
 
        <b><a href="postconf.5.html#mydestination">mydestination</a> ($<a href="postconf.5.html#myhostname">myhostname</a>, localhost.$<a href="postconf.5.html#mydomain">mydomain</a>, localhost)</b>
-              The  list of domains that are delivered via the $<a href="postconf.5.html#local_transport">local_transport</a>
+              The list of domains that are delivered via the  $<a href="postconf.5.html#local_transport">local_transport</a>
               mail delivery transport.
 
        <b><a href="postconf.5.html#myorigin">myorigin</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
-              The domain name that locally-posted mail appears to  come  from,
+              The  domain  name that locally-posted mail appears to come from,
               and that locally posted mail is delivered to.
 
        <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
-              The remote network interface addresses that this mail system re-
+              The remote network interface addresses  that  this  mail  system
-              ceives  mail on by way of a proxy or network address translation
+              receives  mail  on by way of a proxy or network address transla-
-              unit.
+              tion unit.
 
 <b><a name="see_also">SEE ALSO</a></b>
        <a href="trivial-rewrite.8.html">trivial-rewrite(8)</a>, address resolver
@@ -178,5 +178,5 @@
        111 8th Avenue
        New York, NY 10011, USA
 
-                                                                  <i>RELOCATED</i>(5)
+                                                                  RELOCATED(5)
 </pre> </body> </html>

postfix/html/sendmail.1.html

@@ -168,12 +168,32 @@ SENDMAIL(1)                                                        SENDMAIL(1)
               Delivery   status   notification   control.   Specify  either  a
               comma-separated list with one or more of <b>failure</b> (send notifica-
               tion  when delivery fails), <b>delay</b> (send notification when deliv-
-              ery is delayed), or <b>success</b> (send notification when the  message
+              ery is delayed), or <b>success</b> (send notification after the message
               is delivered); or specify <b>never</b> (don't send any notifications at
               all).
 
               This feature is available in Postfix 2.3 and later.
 
+       <b>-O requiretls</b>
+              When delivering a message to an SMTP or LMTP server, the connec-
+              tion  must  use  TLS with a verified server certificate, and the
+              server must support REQUIRETLS. Try multiple servers  if  possi-
+              ble, and return the message as undeliverable when these require-
+              ments were not satisfied with  any  of  the  servers  that  were
+              tried. The "requiretls" option value is case-insensitive.
+
+              This feature is available in Postfix 3.10 and later.
+
+       <b>-O smtputf8</b>
+              When  delivering a message to an SMTP or LMTP server, the server
+              must support SMTPUTF8. Try multiple  servers  if  possible,  and
+              return  the  message as undeliverable when a message contains an
+              UTF8 envelope address or message header, but  SMTPUTF8  was  not
+              supported  by any of the servers that were tried. The "smtputf8"
+              option value is case-insensitive.
+
+              This feature is available in Postfix 3.10 and later.
+
        <b>-n</b> (ignored)
               Backwards compatibility.
 
@@ -483,6 +503,12 @@ SENDMAIL(1)                                                        SENDMAIL(1)
               the  default  Postfix  instance,  and that are started, stopped,
               etc., together with the default Postfix instance.
 
+       Postfix 3.10 and later:
+
+       <b><a href="postconf.5.html#requiretls_enable">requiretls_enable</a> (yes)</b>
+              Enable support for the ESMTP verb "REQUIRETLS", defined  in  <a href="https://tools.ietf.org/html/rfc8689">RFC</a>
+              <a href="https://tools.ietf.org/html/rfc8689">8689</a>.
+
 <b><a name="files">FILES</a></b>
        /var/spool/postfix, mail queue
        /etc/postfix, configuration files
@@ -501,7 +527,7 @@ SENDMAIL(1)                                                        SENDMAIL(1)
        syslogd(8), system logging
 
 <b><a name="readme_files">README_FILES</a></b>
-       Use "<b>postconf <a href="postconf.5.html#readme_directory">readme_directory</a></b>" or "<b>postconf <a href="postconf.5.html#html_directory">html_directory</a></b>" to  locate
+       Use  "<b>postconf <a href="postconf.5.html#readme_directory">readme_directory</a></b>" or "<b>postconf <a href="postconf.5.html#html_directory">html_directory</a></b>" to locate
        this information.
        <a href="DEBUG_README.html">DEBUG_README</a>, Postfix debugging howto
        <a href="ETRN_README.html">ETRN_README</a>, Postfix ETRN howto

postfix/html/smtp.8.html

@@ -174,7 +174,7 @@ SMTP(8)                                                                SMTP(8)
        <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a> (Internationalized SMTP)
        <a href="https://tools.ietf.org/html/rfc6533">RFC 6533</a> (Internationalized Delivery Status Notifications)
        <a href="https://tools.ietf.org/html/rfc7672">RFC 7672</a> (SMTP security via opportunistic DANE TLS)
-       <a href="https://tools.ietf.org/html/rfc8689">RFC 8689</a> (TLS-Required message header)
+       <a href="https://tools.ietf.org/html/rfc8689">RFC 8689</a> (SMTP REQUIRETLS extension)
 
 <b><a name="diagnostics">DIAGNOSTICS</a></b>
        Problems  and  transactions  are  logged  to <b>syslogd</b>(8) or <a href="postlogd.8.html"><b>postlogd</b>(8)</a>.
@@ -507,7 +507,7 @@ SMTP(8)                                                                SMTP(8)
               The delimiter between username and password in  sasl_passwd_maps
               lookup results.
 
-<b><a name="starttls_support_controls">STARTTLS SUPPORT CONTROLS</a></b>
+<b><a name="tls_support_controls">TLS SUPPORT CONTROLS</a></b>
        Detailed  information  about STARTTLS configuration may be found in the
        <a href="TLS_README.html">TLS_README</a> document.
 
@@ -766,41 +766,52 @@ SMTP(8)                                                                SMTP(8)
               Enable  support  for  the  "TLS-Required:  no"  message  header,
               defined in <a href="https://tools.ietf.org/html/rfc8689">RFC 8689</a>.
 
-<b><a name="obsolete_starttls_controls">OBSOLETE STARTTLS CONTROLS</a></b>
+       <b><a href="postconf.5.html#requiretls_enable">requiretls_enable</a> (yes)</b>
-       The following configuration parameters  exist  for  compatibility  with
+              Enable support for the ESMTP verb "REQUIRETLS", defined  in  <a href="https://tools.ietf.org/html/rfc8689">RFC</a>
-       Postfix  versions  before  2.3.  Support for these will be removed in a
+              <a href="https://tools.ietf.org/html/rfc8689">8689</a>.
+
+       <b><a href="postconf.5.html#smtp_enforce_requiretls">smtp_enforce_requiretls</a> (empty)</b>
+              An  optional  list  of  next-hop  destinations  that the Postfix
+              SMTP/LMTP client will enforce REQUIRETLS for, when a message was
+              received  with  the  REQUIRETLS option: the next-hop server must
+              offer a matching TLS server certificate,  and  the  server  must
+              announce REQUIRETLS support).
+
+<b><a name="obsolete_tls_controls">OBSOLETE TLS CONTROLS</a></b>
+       The  following  configuration  parameters  exist for compatibility with
+       Postfix versions before 2.3. Support for these will  be  removed  in  a
        future release.
 
        <b><a href="postconf.5.html#smtp_use_tls">smtp_use_tls</a> (no)</b>
-              Opportunistic mode: use TLS when a remote SMTP server  announces
+              Opportunistic  mode: use TLS when a remote SMTP server announces
               STARTTLS support, otherwise send the mail in the clear.
 
        <b><a href="postconf.5.html#smtp_enforce_tls">smtp_enforce_tls</a> (no)</b>
-              Enforcement  mode:  require  that  remote  SMTP  servers use TLS
+              Enforcement mode: require  that  remote  SMTP  servers  use  TLS
               encryption, and never send mail in the clear.
 
        <b><a href="postconf.5.html#smtp_tls_enforce_peername">smtp_tls_enforce_peername</a> (yes)</b>
-              With mandatory TLS encryption,  require  that  the  remote  SMTP
+              With  mandatory  TLS  encryption,  require  that the remote SMTP
-              server  hostname  matches  the  information  in  the remote SMTP
+              server hostname matches  the  information  in  the  remote  SMTP
               server certificate.
 
        <b><a href="postconf.5.html#smtp_tls_per_site">smtp_tls_per_site</a> (empty)</b>
-              Optional lookup tables with the Postfix SMTP  client  TLS  usage
+              Optional  lookup  tables  with the Postfix SMTP client TLS usage
-              policy  by  next-hop destination and by remote SMTP server host-
+              policy by next-hop destination and by remote SMTP  server  host-
               name.
 
        <b><a href="postconf.5.html#smtp_tls_cipherlist">smtp_tls_cipherlist</a> (empty)</b>
-              Obsolete Postfix &lt; 2.3 control for the Postfix SMTP  client  TLS
+              Obsolete  Postfix  &lt; 2.3 control for the Postfix SMTP client TLS
               cipher list.
 
 <b><a name="resource_and_rate_controls">RESOURCE AND RATE CONTROLS</a></b>
        <b><a href="postconf.5.html#smtp_connect_timeout">smtp_connect_timeout</a> (30s)</b>
-              The  Postfix SMTP client time limit for completing a TCP connec-
+              The Postfix SMTP client time limit for completing a TCP  connec-
               tion, or zero (use the operating system built-in time limit).
 
        <b><a href="postconf.5.html#smtp_helo_timeout">smtp_helo_timeout</a> (300s)</b>
-              The Postfix SMTP client time limit for sending the HELO or  EHLO
+              The  Postfix SMTP client time limit for sending the HELO or EHLO
-              command,  and  for  receiving  the  initial  remote  SMTP server
+              command, and  for  receiving  the  initial  remote  SMTP  server
               response.
 
        <b><a href="postconf.5.html#lmtp_lhlo_timeout">lmtp_lhlo_timeout</a> (300s)</b>
@@ -812,19 +823,19 @@ SMTP(8)                                                                SMTP(8)
               mand, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_mail_timeout">smtp_mail_timeout</a> (300s)</b>
-              The Postfix SMTP client time limit for  sending  the  MAIL  FROM
+              The  Postfix  SMTP  client  time limit for sending the MAIL FROM
               command, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_rcpt_timeout">smtp_rcpt_timeout</a> (300s)</b>
-              The  Postfix SMTP client time limit for sending the SMTP RCPT TO
+              The Postfix SMTP client time limit for sending the SMTP RCPT  TO
               command, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_data_init_timeout">smtp_data_init_timeout</a> (120s)</b>
-              The Postfix SMTP client time limit for  sending  the  SMTP  DATA
+              The  Postfix  SMTP  client  time limit for sending the SMTP DATA
               command, and for receiving the remote SMTP server response.
 
        <b><a href="postconf.5.html#smtp_data_xfer_timeout">smtp_data_xfer_timeout</a> (180s)</b>
-              The  Postfix SMTP client time limit for sending the SMTP message
+              The Postfix SMTP client time limit for sending the SMTP  message
               content.
 
        <b><a href="postconf.5.html#smtp_data_done_timeout">smtp_data_done_timeout</a> (600s)</b>
@@ -838,13 +849,13 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 2.1 and later:
 
        <b><a href="postconf.5.html#smtp_mx_address_limit">smtp_mx_address_limit</a> (5)</b>
-              The maximal number of MX (mail exchanger) IP addresses that  can
+              The  maximal number of MX (mail exchanger) IP addresses that can
-              result  from Postfix SMTP client mail exchanger lookups, or zero
+              result from Postfix SMTP client mail exchanger lookups, or  zero
               (no limit).
 
        <b><a href="postconf.5.html#smtp_mx_session_limit">smtp_mx_session_limit</a> (2)</b>
-              The maximal number of SMTP sessions per delivery request  before
+              The  maximal number of SMTP sessions per delivery request before
-              the  Postfix  SMTP  client  gives  up or delivers to a fall-back
+              the Postfix SMTP client gives up  or  delivers  to  a  fall-back
               <a href="postconf.5.html#relayhost">relay host</a>, or zero (no limit).
 
        <b><a href="postconf.5.html#smtp_rset_timeout">smtp_rset_timeout</a> (20s)</b>
@@ -854,17 +865,17 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 2.2 and earlier:
 
        <b><a href="postconf.5.html#lmtp_cache_connection">lmtp_cache_connection</a> (yes)</b>
-              Keep  Postfix  LMTP  client connections open for up to $<a href="postconf.5.html#max_idle">max_idle</a>
+              Keep Postfix LMTP client connections open for  up  to  $<a href="postconf.5.html#max_idle">max_idle</a>
               seconds.
 
        Available in Postfix version 2.2 and later:
 
        <b><a href="postconf.5.html#smtp_connection_cache_destinations">smtp_connection_cache_destinations</a> (empty)</b>
-              Permanently enable SMTP connection  caching  for  the  specified
+              Permanently  enable  SMTP  connection  caching for the specified
               destinations.
 
        <b><a href="postconf.5.html#smtp_connection_cache_on_demand">smtp_connection_cache_on_demand</a> (yes)</b>
-              Temporarily  enable  SMTP connection caching while a destination
+              Temporarily enable SMTP connection caching while  a  destination
               has a high volume of mail in the <a href="QSHAPE_README.html#active_queue">active queue</a>.
 
        <b><a href="postconf.5.html#smtp_connection_reuse_time_limit">smtp_connection_reuse_time_limit</a> (300s)</b>
@@ -878,23 +889,23 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 2.3 and later:
 
        <b><a href="postconf.5.html#connection_cache_protocol_timeout">connection_cache_protocol_timeout</a> (5s)</b>
-              Time limit for connection cache connect, send or receive  opera-
+              Time  limit for connection cache connect, send or receive opera-
               tions.
 
        Available in Postfix version 2.9 - 3.6:
 
        <b><a href="postconf.5.html#smtp_per_record_deadline">smtp_per_record_deadline</a> (no)</b>
-              Change  the  behavior  of the smtp_*_timeout time limits, from a
+              Change the behavior of the smtp_*_timeout time  limits,  from  a
-              time limit per read or write system call, to  a  time  limit  to
+              time  limit  per  read  or write system call, to a time limit to
-              send  or  receive  a complete record (an SMTP command line, SMTP
+              send or receive a complete record (an SMTP  command  line,  SMTP
-              response line, SMTP message content line, or TLS  protocol  mes-
+              response  line,  SMTP message content line, or TLS protocol mes-
               sage).
 
        Available in Postfix version 2.11 and later:
 
        <b><a href="postconf.5.html#smtp_connection_reuse_count_limit">smtp_connection_reuse_count_limit</a> (0)</b>
-              When  SMTP  connection  caching  is enabled, the number of times
+              When SMTP connection caching is enabled,  the  number  of  times
-              that an SMTP session may be reused before it is closed, or  zero
+              that  an SMTP session may be reused before it is closed, or zero
               (no limit).
 
        Available in Postfix version 3.4 and later:
@@ -905,13 +916,13 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix version 3.7 and later:
 
        <b><a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a> (no)</b>
-              Change  the  behavior  of the smtp_*_timeout time limits, from a
+              Change the behavior of the smtp_*_timeout time  limits,  from  a
-              time limit per plaintext or TLS read or write call,  to  a  com-
+              time  limit  per  plaintext or TLS read or write call, to a com-
-              bined  time  limit  for  sending a complete SMTP request and for
+              bined time limit for sending a complete  SMTP  request  and  for
               receiving a complete SMTP response.
 
        <b><a href="postconf.5.html#smtp_min_data_rate">smtp_min_data_rate</a> (500)</b>
-              The minimum plaintext data transfer  rate  in  bytes/second  for
+              The  minimum  plaintext  data  transfer rate in bytes/second for
               DATA    requests,    when    deadlines    are    enabled    with
               <a href="postconf.5.html#smtp_per_request_deadline">smtp_per_request_deadline</a>.
 
@@ -919,54 +930,54 @@ SMTP(8)                                                                SMTP(8)
 
        <b><a href="postconf.5.html#transport_destination_concurrency_limit">transport_destination_concurrency_limit</a>   ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destination_concur</a>-</b>
        <b><a href="postconf.5.html#default_destination_concurrency_limit">rency_limit</a>)</b>
-              A transport-specific override for  the  <a href="postconf.5.html#default_destination_concurrency_limit">default_destination_con</a>-
+              A  transport-specific  override for the <a href="postconf.5.html#default_destination_concurrency_limit">default_destination_con</a>-
               <a href="postconf.5.html#default_destination_concurrency_limit">currency_limit</a> parameter value, where <i>transport</i> is the <a href="master.5.html">master.cf</a>
               name of the message delivery transport.
 
        <b><a href="postconf.5.html#transport_destination_recipient_limit">transport_destination_recipient_limit</a>     ($<a href="postconf.5.html#default_destination_recipient_limit">default_destination_recipi</a>-</b>
        <b><a href="postconf.5.html#default_destination_recipient_limit">ent_limit</a>)</b>
               A transport-specific override for the <a href="postconf.5.html#default_destination_recipient_limit">default_destination_recip</a>-
-              <a href="postconf.5.html#default_destination_recipient_limit">ient_limit</a>  parameter  value,  where  <i>transport</i> is the <a href="master.5.html">master.cf</a>
+              <a href="postconf.5.html#default_destination_recipient_limit">ient_limit</a> parameter value, where  <i>transport</i>  is  the  <a href="master.5.html">master.cf</a>
               name of the message delivery transport.
 
 <b><a name="smtputf8_controls">SMTPUTF8 CONTROLS</a></b>
        Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
 
        <b><a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a> (yes)</b>
-              Enable preliminary SMTPUTF8 support for the protocols  described
+              Enable  preliminary SMTPUTF8 support for the protocols described
               in <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a>, <a href="https://tools.ietf.org/html/rfc6532">RFC 6532</a>, and <a href="https://tools.ietf.org/html/rfc6533">RFC 6533</a>.
 
        <b><a href="postconf.5.html#smtputf8_autodetect_classes">smtputf8_autodetect_classes</a> (sendmail, verify)</b>
-              Detect  that  a message requires SMTPUTF8 support for the speci-
+              Detect that a message requires SMTPUTF8 support for  the  speci-
               fied mail origin classes.
 
        Available in Postfix version 3.2 and later:
 
        <b><a href="postconf.5.html#enable_idna2003_compatibility">enable_idna2003_compatibility</a> (no)</b>
-              Enable  'transitional'  compatibility   between   IDNA2003   and
+              Enable   'transitional'   compatibility   between  IDNA2003  and
-              IDNA2008,  when  converting UTF-8 domain names to/from the ASCII
+              IDNA2008, when converting UTF-8 domain names to/from  the  ASCII
               form that is used for DNS lookups.
 
 <b><a name="trouble_shooting_controls">TROUBLE SHOOTING CONTROLS</a></b>
        <b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
-              The increment in verbose logging level when a  nexthop  destina-
+              The  increment  in verbose logging level when a nexthop destina-
-              tion,  remote client or server name or network address matches a
+              tion, remote client or server name or network address matches  a
               pattern given with the <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
 
        <b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
-              Optional list of nexthop destination, remote  client  or  server
+              Optional  list  of  nexthop destination, remote client or server
-              name  or  network  address  patterns that, if matched, cause the
+              name or network address patterns that,  if  matched,  cause  the
-              verbose logging level to increase by  the  amount  specified  in
+              verbose  logging  level  to  increase by the amount specified in
               $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
 
        <b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
-              The  recipient  of  postmaster notifications about mail delivery
+              The recipient of postmaster notifications  about  mail  delivery
               problems that are caused by policy, resource, software or proto-
               col errors.
 
        <b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b>
-              What   categories  of  Postfix-generated  mail  are  subject  to
+              What  categories  of  Postfix-generated  mail  are  subject   to
-              before-queue   content    inspection    by    <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>,
+              before-queue    content    inspection    by   <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>,
               <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>.
 
        <b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b>
@@ -974,46 +985,46 @@ SMTP(8)                                                                SMTP(8)
 
 <b><a name="miscellaneous_controls">MISCELLANEOUS CONTROLS</a></b>
        <b><a href="postconf.5.html#best_mx_transport">best_mx_transport</a> (empty)</b>
-              Where  the  Postfix  SMTP  client  should  deliver  mail when it
+              Where the Postfix  SMTP  client  should  deliver  mail  when  it
               detects a "mail loops back to myself" error condition.
 
        <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
-              The default location of the Postfix <a href="postconf.5.html">main.cf</a> and  <a href="master.5.html">master.cf</a>  con-
+              The  default  location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
               figuration files.
 
        <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
-              How  much  time  a  Postfix  daemon process may take to handle a
+              How much time a Postfix daemon process  may  take  to  handle  a
               request before it is terminated by a built-in watchdog timer.
 
        <b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b>
-              The maximal number of digits after the decimal point  when  log-
+              The  maximal  number of digits after the decimal point when log-
               ging delay values.
 
        <b><a href="postconf.5.html#disable_dns_lookups">disable_dns_lookups</a> (no)</b>
               Disable DNS lookups in the Postfix SMTP and LMTP clients.
 
        <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
-              The  local  network  interface  addresses  that this mail system
+              The local network interface  addresses  that  this  mail  system
               receives mail on.
 
        <b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (see 'postconf -d' output)</b>
-              The Internet protocols Postfix will attempt to use  when  making
+              The  Internet  protocols Postfix will attempt to use when making
               or accepting connections.
 
        <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
-              The  time  limit  for  sending  or receiving information over an
+              The time limit for sending  or  receiving  information  over  an
               internal communication channel.
 
        <b><a href="postconf.5.html#lmtp_assume_final">lmtp_assume_final</a> (no)</b>
-              When a remote LMTP server announces no DSN support, assume  that
+              When  a remote LMTP server announces no DSN support, assume that
-              the  server performs final delivery, and send "delivered" deliv-
+              the server performs final delivery, and send "delivered"  deliv-
               ery status notifications instead of "relayed".
 
        <b><a href="postconf.5.html#lmtp_tcp_port">lmtp_tcp_port</a> (24)</b>
               The default TCP port that the Postfix LMTP client connects to.
 
        <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
-              The maximum amount of time that an idle Postfix  daemon  process
+              The  maximum  amount of time that an idle Postfix daemon process
               waits for an incoming connection before terminating voluntarily.
 
        <b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
@@ -1027,21 +1038,21 @@ SMTP(8)                                                                SMTP(8)
               The process name of a Postfix command or daemon process.
 
        <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
-              The  remote  network  interface  addresses that this mail system
+              The remote network interface addresses  that  this  mail  system
-              receives mail on by way of a proxy or network  address  transla-
+              receives  mail  on by way of a proxy or network address transla-
               tion unit.
 
        <b><a href="postconf.5.html#smtp_address_preference">smtp_address_preference</a> (any)</b>
               The address type ("ipv6", "ipv4" or "any") that the Postfix SMTP
-              client will try first, when a  destination  has  IPv6  and  IPv4
+              client  will  try  first,  when  a destination has IPv6 and IPv4
               addresses with equal MX preference.
 
        <b><a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> (empty)</b>
-              An  optional  numerical  network  address  that the Postfix SMTP
+              An optional numerical network  address  that  the  Postfix  SMTP
               client should bind to when making an IPv4 connection.
 
        <b><a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> (empty)</b>
-              An optional numerical network  address  that  the  Postfix  SMTP
+              An  optional  numerical  network  address  that the Postfix SMTP
               client should bind to when making an IPv6 connection.
 
        <b><a href="postconf.5.html#smtp_helo_name">smtp_helo_name</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
@@ -1061,7 +1072,7 @@ SMTP(8)                                                                SMTP(8)
               The syslog facility of Postfix logging.
 
        <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
-              A prefix that  is  prepended  to  the  process  name  in  syslog
+              A  prefix  that  is  prepended  to  the  process  name in syslog
               records, so that, for example, "smtpd" becomes "prefix/smtpd".
 
        Available with Postfix 2.2 and earlier:
@@ -1073,14 +1084,14 @@ SMTP(8)                                                                SMTP(8)
        Available with Postfix 2.3 and later:
 
        <b><a href="postconf.5.html#smtp_fallback_relay">smtp_fallback_relay</a> ($<a href="postconf.5.html#fallback_relay">fallback_relay</a>)</b>
-              Optional list of relay destinations that will be  used  when  an
+              Optional  list  of  relay destinations that will be used when an
-              SMTP  destination  is not found, or when delivery fails due to a
+              SMTP destination is not found, or when delivery fails due  to  a
               non-permanent error.
 
        Available with Postfix 3.0 and later:
 
        <b><a href="postconf.5.html#smtp_address_verify_target">smtp_address_verify_target</a> (rcpt)</b>
-              In the context of email address verification, the SMTP  protocol
+              In  the context of email address verification, the SMTP protocol
               stage that determines whether an email address is deliverable.
 
        Available with Postfix 3.1 and later:
@@ -1102,7 +1113,7 @@ SMTP(8)                                                                SMTP(8)
        Available in Postfix 3.7 and later:
 
        <b><a href="postconf.5.html#smtp_bind_address_enforce">smtp_bind_address_enforce</a> (no)</b>
-              Defer delivery when the Postfix SMTP  client  cannot  apply  the
+              Defer  delivery  when  the  Postfix SMTP client cannot apply the
               <a href="postconf.5.html#smtp_bind_address">smtp_bind_address</a> or <a href="postconf.5.html#smtp_bind_address6">smtp_bind_address6</a> setting.
 
 <b><a name="see_also">SEE ALSO</a></b>

postfix/html/smtpd.8.html

@@ -62,6 +62,7 @@ SMTPD(8)                                                              SMTPD(8)
        <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a> (Internationalized SMTP)
        <a href="https://tools.ietf.org/html/rfc6533">RFC 6533</a> (Internationalized Delivery Status Notifications)
        <a href="https://tools.ietf.org/html/rfc7505">RFC 7505</a> ("Null MX" No Service Resource Record)
+       <a href="https://tools.ietf.org/html/rfc8689">RFC 8689</a> (SMTP REQUIRETLS extension)
 
 <b><a name="diagnostics">DIAGNOSTICS</a></b>
        Problems and transactions are logged to <b>syslogd</b>(8) or <a href="postlogd.8.html"><b>postlogd</b>(8)</a>.
@@ -430,7 +431,7 @@ SMTPD(8)                                                              SMTPD(8)
               If  non-empty,  a  filter  for the SASL mechanism names that the
               Postfix SMTP server will announce in the EHLO response.
 
-<b><a name="starttls_support_controls">STARTTLS SUPPORT CONTROLS</a></b>
+<b><a name="tls_support_controls">TLS SUPPORT CONTROLS</a></b>
        Detailed information about STARTTLS configuration may be found  in  the
        <a href="TLS_README.html">TLS_README</a> document.
 
@@ -655,109 +656,115 @@ SMTPD(8)                                                              SMTPD(8)
               instead of an X.509 certificate, when asking  for  or  requiring
               client authentication.
 
-<b><a name="obsolete_starttls_controls">OBSOLETE STARTTLS CONTROLS</a></b>
+       Available in Postfix version 3.10 and later:
-       The  following  configuration  parameters  exist for compatibility with
+
-       Postfix versions before 2.3. Support for these will  be  removed  in  a
+       <b><a href="postconf.5.html#requiretls_enable">requiretls_enable</a> (yes)</b>
+              Enable  support  for the ESMTP verb "REQUIRETLS", defined in <a href="https://tools.ietf.org/html/rfc8689">RFC</a>
+              <a href="https://tools.ietf.org/html/rfc8689">8689</a>.
+
+<b><a name="obsolete_tls_controls">OBSOLETE TLS CONTROLS</a></b>
+       The following configuration parameters  exist  for  compatibility  with
+       Postfix  versions  before  2.3.  Support for these will be removed in a
        future release.
 
        <b><a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a> (no)</b>
-              Opportunistic  TLS:  announce  STARTTLS  support  to remote SMTP
+              Opportunistic TLS: announce  STARTTLS  support  to  remote  SMTP
               clients, but do not require that clients use TLS encryption.
 
        <b><a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a> (no)</b>
               Mandatory TLS: announce STARTTLS support to remote SMTP clients,
-              and  reject  all  plaintext commands except HELO, EHLO, XCLIENT,
+              and reject all plaintext commands except  HELO,  EHLO,  XCLIENT,
               STARTTLS, NOOP, QUIT, and (Postfix &gt;= 3.9) HELP.
 
        <b><a href="postconf.5.html#smtpd_tls_cipherlist">smtpd_tls_cipherlist</a> (empty)</b>
-              Obsolete Postfix &lt; 2.3 control for the Postfix SMTP  server  TLS
+              Obsolete  Postfix  &lt; 2.3 control for the Postfix SMTP server TLS
               cipher list.
 
 <b><a name="smtputf8_controls">SMTPUTF8 CONTROLS</a></b>
        Preliminary SMTPUTF8 support is introduced with Postfix 3.0.
 
        <b><a href="postconf.5.html#smtputf8_enable">smtputf8_enable</a> (yes)</b>
-              Enable  preliminary SMTPUTF8 support for the protocols described
+              Enable preliminary SMTPUTF8 support for the protocols  described
               in <a href="https://tools.ietf.org/html/rfc6531">RFC 6531</a>, <a href="https://tools.ietf.org/html/rfc6532">RFC 6532</a>, and <a href="https://tools.ietf.org/html/rfc6533">RFC 6533</a>.
 
        <b><a href="postconf.5.html#strict_smtputf8">strict_smtputf8</a> (no)</b>
               Enable stricter enforcement of the SMTPUTF8 protocol.
 
        <b><a href="postconf.5.html#smtputf8_autodetect_classes">smtputf8_autodetect_classes</a> (sendmail, verify)</b>
-              Detect that a message requires SMTPUTF8 support for  the  speci-
+              Detect  that  a message requires SMTPUTF8 support for the speci-
               fied mail origin classes.
 
        Available in Postfix version 3.2 and later:
 
        <b><a href="postconf.5.html#enable_idna2003_compatibility">enable_idna2003_compatibility</a> (no)</b>
-              Enable   'transitional'   compatibility   between  IDNA2003  and
+              Enable  'transitional'  compatibility   between   IDNA2003   and
-              IDNA2008, when converting UTF-8 domain names to/from  the  ASCII
+              IDNA2008,  when  converting UTF-8 domain names to/from the ASCII
               form that is used for DNS lookups.
 
 <b><a name="verp_support_controls">VERP SUPPORT CONTROLS</a></b>
-       With  VERP  style delivery, each recipient of a message receives a cus-
+       With VERP style delivery, each recipient of a message receives  a  cus-
-       tomized copy of the message with his/her own recipient address  encoded
+       tomized  copy of the message with his/her own recipient address encoded
        in the envelope sender address.  The <a href="VERP_README.html">VERP_README</a> file describes config-
-       uration and operation details of Postfix support for variable  envelope
+       uration  and operation details of Postfix support for variable envelope
-       return  path addresses.  VERP style delivery is requested with the SMTP
+       return path addresses.  VERP style delivery is requested with the  SMTP
-       XVERP command or with the "sendmail  -V"  command-line  option  and  is
+       XVERP  command  or  with  the  "sendmail -V" command-line option and is
        available in Postfix version 1.1 and later.
 
        <b><a href="postconf.5.html#default_verp_delimiters">default_verp_delimiters</a> (+=)</b>
               The two default VERP delimiter characters.
 
        <b><a href="postconf.5.html#verp_delimiter_filter">verp_delimiter_filter</a> (-=+)</b>
-              The  characters  Postfix accepts as VERP delimiter characters on
+              The characters Postfix accepts as VERP delimiter  characters  on
               the Postfix <a href="sendmail.1.html"><b>sendmail</b>(1)</a> command line and in SMTP commands.
 
        Available in Postfix version 1.1 and 2.0:
 
        <b><a href="postconf.5.html#authorized_verp_clients">authorized_verp_clients</a> ($<a href="postconf.5.html#mynetworks">mynetworks</a>)</b>
-              What remote SMTP clients are allowed to specify the  XVERP  com-
+              What  remote  SMTP clients are allowed to specify the XVERP com-
               mand.
 
        Available in Postfix version 2.1 and later:
 
        <b><a href="postconf.5.html#smtpd_authorized_verp_clients">smtpd_authorized_verp_clients</a> ($<a href="postconf.5.html#authorized_verp_clients">authorized_verp_clients</a>)</b>
-              What  remote  SMTP clients are allowed to specify the XVERP com-
+              What remote SMTP clients are allowed to specify the  XVERP  com-
               mand.
 
 <b><a name="trouble_shooting_controls">TROUBLE SHOOTING CONTROLS</a></b>
-       The <a href="DEBUG_README.html">DEBUG_README</a> document describes how to debug parts of  the  Postfix
+       The  <a href="DEBUG_README.html">DEBUG_README</a>  document describes how to debug parts of the Postfix
-       mail  system.  The  methods  vary from making the software log a lot of
+       mail system. The methods vary from making the software  log  a  lot  of
        detail, to running some daemon processes under control of a call tracer
        or debugger.
 
        <b><a href="postconf.5.html#debug_peer_level">debug_peer_level</a> (2)</b>
-              The  increment  in verbose logging level when a nexthop destina-
+              The increment in verbose logging level when a  nexthop  destina-
-              tion, remote client or server name or network address matches  a
+              tion,  remote client or server name or network address matches a
               pattern given with the <a href="postconf.5.html#debug_peer_list">debug_peer_list</a> parameter.
 
        <b><a href="postconf.5.html#debug_peer_list">debug_peer_list</a> (empty)</b>
-              Optional  list  of  nexthop destination, remote client or server
+              Optional list of nexthop destination, remote  client  or  server
-              name or network address patterns that,  if  matched,  cause  the
+              name  or  network  address  patterns that, if matched, cause the
-              verbose  logging  level  to  increase by the amount specified in
+              verbose logging level to increase by  the  amount  specified  in
               $<a href="postconf.5.html#debug_peer_level">debug_peer_level</a>.
 
        <b><a href="postconf.5.html#error_notice_recipient">error_notice_recipient</a> (postmaster)</b>
-              The recipient of postmaster notifications  about  mail  delivery
+              The  recipient  of  postmaster notifications about mail delivery
               problems that are caused by policy, resource, software or proto-
               col errors.
 
        <b><a href="postconf.5.html#internal_mail_filter_classes">internal_mail_filter_classes</a> (empty)</b>
-              What  categories  of  Postfix-generated  mail  are  subject   to
+              What   categories  of  Postfix-generated  mail  are  subject  to
-              before-queue    content    inspection    by   <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>,
+              before-queue   content    inspection    by    <a href="postconf.5.html#non_smtpd_milters">non_smtpd_milters</a>,
               <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>.
 
        <b><a href="postconf.5.html#notify_classes">notify_classes</a> (resource, software)</b>
               The list of error classes that are reported to the postmaster.
 
        <b><a href="postconf.5.html#smtpd_reject_footer">smtpd_reject_footer</a> (empty)</b>
-              Optional information that is appended after  each  Postfix  SMTP
+              Optional  information  that  is appended after each Postfix SMTP
               server 4XX or 5XX response.
 
        <b><a href="postconf.5.html#soft_bounce">soft_bounce</a> (no)</b>
-              Safety  net to keep mail queued that would otherwise be returned
+              Safety net to keep mail queued that would otherwise be  returned
               to the sender.
 
        Available in Postfix version 2.1 and later:
@@ -768,49 +775,49 @@ SMTPD(8)                                                              SMTPD(8)
        Available in Postfix version 2.10 and later:
 
        <b><a href="postconf.5.html#smtpd_log_access_permit_actions">smtpd_log_access_permit_actions</a> (empty)</b>
-              Enable  logging  of  the  named  "permit" actions in SMTP server
+              Enable logging of the named  "permit"  actions  in  SMTP  server
-              access lists (by default, the SMTP server logs "reject"  actions
+              access  lists (by default, the SMTP server logs "reject" actions
               but not "permit" actions).
 
 <b><a name="known_versus_unknown_recipient_controls">KNOWN VERSUS UNKNOWN RECIPIENT CONTROLS</a></b>
-       As  of  Postfix  version  2.0, the SMTP server rejects mail for unknown
+       As of Postfix version 2.0, the SMTP server  rejects  mail  for  unknown
        recipients. This prevents the mail queue from clogging up with undeliv-
-       erable  MAILER-DAEMON messages. Additional information on this topic is
+       erable MAILER-DAEMON messages. Additional information on this topic  is
        in the <a href="LOCAL_RECIPIENT_README.html">LOCAL_RECIPIENT_README</a> and <a href="ADDRESS_CLASS_README.html">ADDRESS_CLASS_README</a> documents.
 
        <b><a href="postconf.5.html#show_user_unknown_table_name">show_user_unknown_table_name</a> (yes)</b>
-              Display the name of the recipient table in  the  "User  unknown"
+              Display  the  name  of the recipient table in the "User unknown"
               responses.
 
        <b><a href="postconf.5.html#canonical_maps">canonical_maps</a> (empty)</b>
-              Optional  address  mapping lookup tables for message headers and
+              Optional address mapping lookup tables for message  headers  and
               envelopes.
 
        <b><a href="postconf.5.html#recipient_canonical_maps">recipient_canonical_maps</a> (empty)</b>
-              Optional address mapping lookup tables for envelope  and  header
+              Optional  address  mapping lookup tables for envelope and header
               recipient addresses.
 
        <b><a href="postconf.5.html#sender_canonical_maps">sender_canonical_maps</a> (empty)</b>
-              Optional  address  mapping lookup tables for envelope and header
+              Optional address mapping lookup tables for envelope  and  header
               sender addresses.
 
        Parameters concerning known/unknown local recipients:
 
        <b><a href="postconf.5.html#mydestination">mydestination</a> ($<a href="postconf.5.html#myhostname">myhostname</a>, localhost.$<a href="postconf.5.html#mydomain">mydomain</a>, localhost)</b>
-              The list of domains that are delivered via the  $<a href="postconf.5.html#local_transport">local_transport</a>
+              The  list of domains that are delivered via the $<a href="postconf.5.html#local_transport">local_transport</a>
               mail delivery transport.
 
        <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a> (all)</b>
-              The  local  network  interface  addresses  that this mail system
+              The local network interface  addresses  that  this  mail  system
               receives mail on.
 
        <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a> (empty)</b>
-              The remote network interface addresses  that  this  mail  system
+              The  remote  network  interface  addresses that this mail system
-              receives  mail  on by way of a proxy or network address transla-
+              receives mail on by way of a proxy or network  address  transla-
               tion unit.
 
        <b><a href="postconf.5.html#inet_protocols">inet_protocols</a> (see 'postconf -d' output)</b>
-              The Internet protocols Postfix will attempt to use  when  making
+              The  Internet  protocols Postfix will attempt to use when making
               or accepting connections.
 
        <b><a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> (<a href="proxymap.8.html">proxy</a>:unix:passwd.byname $<a href="postconf.5.html#alias_maps">alias_maps</a>)</b>
@@ -819,61 +826,61 @@ SMTPD(8)                                                              SMTPD(8)
 
        <b><a href="postconf.5.html#unknown_local_recipient_reject_code">unknown_local_recipient_reject_code</a> (550)</b>
               The numerical Postfix SMTP server response code when a recipient
-              address  is local, and $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> specifies a list of
+              address is local, and $<a href="postconf.5.html#local_recipient_maps">local_recipient_maps</a> specifies a list  of
               lookup tables that does not match the recipient.
 
        Parameters concerning known/unknown recipients of relay destinations:
 
        <b><a href="postconf.5.html#relay_domains">relay_domains</a> (Postfix</b> &gt;<b>= 3.0: empty, Postfix</b> &lt; <b>3.0: $<a href="postconf.5.html#mydestination">mydestination</a>)</b>
-              What destination domains (and subdomains  thereof)  this  system
+              What  destination  domains  (and subdomains thereof) this system
               will relay mail to.
 
        <b><a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> (empty)</b>
-              Optional  lookup  tables with all valid addresses in the domains
+              Optional lookup tables with all valid addresses in  the  domains
               that match $<a href="postconf.5.html#relay_domains">relay_domains</a>.
 
        <b><a href="postconf.5.html#unknown_relay_recipient_reject_code">unknown_relay_recipient_reject_code</a> (550)</b>
-              The numerical Postfix SMTP server reply code  when  a  recipient
+              The  numerical  Postfix  SMTP server reply code when a recipient
-              address  matches $<a href="postconf.5.html#relay_domains">relay_domains</a>, and <a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a> speci-
+              address matches $<a href="postconf.5.html#relay_domains">relay_domains</a>, and <a href="postconf.5.html#relay_recipient_maps">relay_recipient_maps</a>  speci-
-              fies a list of lookup tables that does not match  the  recipient
+              fies  a  list of lookup tables that does not match the recipient
               address.
 
-       Parameters   concerning   known/unknown  recipients  in  virtual  alias
+       Parameters  concerning  known/unknown  recipients  in   virtual   alias
        domains:
 
        <b><a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a> ($<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>)</b>
-              Postfix is the final destination for the specified list of  vir-
+              Postfix  is the final destination for the specified list of vir-
               tual alias domains, that is, domains for which all addresses are
               aliased to addresses in other local or remote domains.
 
        <b><a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> ($<a href="postconf.5.html#virtual_maps">virtual_maps</a>)</b>
               Optional lookup tables that are often searched with a full email
-              address  (including  domain)  and  that apply to all recipients:
+              address (including domain) and that  apply  to  all  recipients:
-              <a href="local.8.html"><b>local</b>(8)</a>, virtual, and remote; this is  unlike  <a href="postconf.5.html#alias_maps">alias_maps</a>  that
+              <a href="local.8.html"><b>local</b>(8)</a>,  virtual,  and  remote; this is unlike <a href="postconf.5.html#alias_maps">alias_maps</a> that
-              are  only  searched  with an email address localpart (no domain)
+              are only searched with an email address  localpart  (no  domain)
               and that apply only to <a href="local.8.html"><b>local</b>(8)</a> recipients.
 
        <b><a href="postconf.5.html#unknown_virtual_alias_reject_code">unknown_virtual_alias_reject_code</a> (550)</b>
-              The Postfix SMTP server reply  code  when  a  recipient  address
+              The  Postfix  SMTP  server  reply  code when a recipient address
-              matches  $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>,  and $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> speci-
+              matches $<a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a>, and  $<a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a>  speci-
-              fies a list of lookup tables that does not match  the  recipient
+              fies  a  list of lookup tables that does not match the recipient
               address.
 
        Parameters  concerning  known/unknown  recipients  in  virtual  mailbox
        domains:
 
        <b><a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a> ($<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>)</b>
-              Postfix is the final  destination  for  the  specified  list  of
+              Postfix  is  the  final  destination  for  the specified list of
-              domains;  mail  is  delivered  via  the  $<a href="postconf.5.html#virtual_transport">virtual_transport</a> mail
+              domains; mail  is  delivered  via  the  $<a href="postconf.5.html#virtual_transport">virtual_transport</a>  mail
               delivery transport.
 
        <b><a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a> (empty)</b>
-              Optional lookup tables with all valid addresses in  the  domains
+              Optional  lookup  tables with all valid addresses in the domains
               that match $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>.
 
        <b><a href="postconf.5.html#unknown_virtual_mailbox_reject_code">unknown_virtual_mailbox_reject_code</a> (550)</b>
-              The  Postfix  SMTP  server  reply  code when a recipient address
+              The Postfix SMTP server reply  code  when  a  recipient  address
-              matches  $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>,   and   $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>
+              matches   $<a href="postconf.5.html#virtual_mailbox_domains">virtual_mailbox_domains</a>,   and  $<a href="postconf.5.html#virtual_mailbox_maps">virtual_mailbox_maps</a>
               specifies a list of lookup tables that does not match the recip-
               ient address.
 
@@ -882,7 +889,7 @@ SMTPD(8)                                                              SMTPD(8)
        control client request rates.
 
        <b><a href="postconf.5.html#line_length_limit">line_length_limit</a> (2048)</b>
-              Upon  input,  long  lines  are chopped up into pieces of at most
+              Upon input, long lines are chopped up into  pieces  of  at  most
               this length; upon delivery, long lines are reconstructed.
 
        <b><a href="postconf.5.html#queue_minfree">queue_minfree</a> (0)</b>
@@ -890,62 +897,62 @@ SMTPD(8)                                                              SMTPD(8)
               tem that is needed to receive mail.
 
        <b><a href="postconf.5.html#message_size_limit">message_size_limit</a> (10240000)</b>
-              The  maximal  size  in  bytes  of  a message, including envelope
+              The maximal size in  bytes  of  a  message,  including  envelope
               information.
 
        <b><a href="postconf.5.html#smtpd_recipient_limit">smtpd_recipient_limit</a> (1000)</b>
-              The maximal number of recipients that the  Postfix  SMTP  server
+              The  maximal  number  of recipients that the Postfix SMTP server
               accepts per message delivery request.
 
        <b><a href="postconf.5.html#smtpd_timeout">smtpd_timeout</a> (normal: 300s, <a href="STRESS_README.html">overload</a>: 10s)</b>
-              When  the  Postfix  SMTP  server  wants  to  send an SMTP server
+              When the Postfix SMTP  server  wants  to  send  an  SMTP  server
-              response, how long the Postfix SMTP  server  will  wait  for  an
+              response,  how  long  the  Postfix  SMTP server will wait for an
-              underlying  network  write  operation  to complete; and when the
+              underlying network write operation to  complete;  and  when  the
-              Postfix SMTP server Postfix wants  to  receive  an  SMTP  client
+              Postfix  SMTP  server  Postfix  wants  to receive an SMTP client
-              request,  how  long  the  Postfix  SMTP  server will wait for an
+              request, how long the Postfix  SMTP  server  will  wait  for  an
               underlying network read operation to complete.
 
        <b><a href="postconf.5.html#smtpd_history_flush_threshold">smtpd_history_flush_threshold</a> (100)</b>
-              The maximal number of lines in the Postfix SMTP  server  command
+              The  maximal  number of lines in the Postfix SMTP server command
-              history  before it is flushed upon receipt of EHLO, RSET, or end
+              history before it is flushed upon receipt of EHLO, RSET, or  end
               of DATA.
 
        Available in Postfix version 2.3 and later:
 
        <b><a href="postconf.5.html#smtpd_peername_lookup">smtpd_peername_lookup</a> (yes)</b>
-              Attempt to look up the remote SMTP client hostname,  and  verify
+              Attempt  to  look up the remote SMTP client hostname, and verify
               that the name matches the client IP address.
 
        The per SMTP client connection count and request rate limits are imple-
-       mented in co-operation with the <a href="anvil.8.html"><b>anvil</b>(8)</a> service, and are available  in
+       mented  in co-operation with the <a href="anvil.8.html"><b>anvil</b>(8)</a> service, and are available in
        Postfix version 2.2 and later.
 
        <b><a href="postconf.5.html#smtpd_client_connection_count_limit">smtpd_client_connection_count_limit</a> (50)</b>
-              How  many simultaneous connections any client is allowed to make
+              How many simultaneous connections any client is allowed to  make
               to this service.
 
        <b><a href="postconf.5.html#smtpd_client_connection_rate_limit">smtpd_client_connection_rate_limit</a> (0)</b>
-              The maximal number of connection attempts any client is  allowed
+              The  maximal number of connection attempts any client is allowed
               to make to this service per time unit.
 
        <b><a href="postconf.5.html#smtpd_client_message_rate_limit">smtpd_client_message_rate_limit</a> (0)</b>
-              The  maximal number of message delivery requests that any client
+              The maximal number of message delivery requests that any  client
-              is allowed to make to this service per time unit, regardless  of
+              is  allowed to make to this service per time unit, regardless of
               whether or not Postfix actually accepts those messages.
 
        <b><a href="postconf.5.html#smtpd_client_recipient_rate_limit">smtpd_client_recipient_rate_limit</a> (0)</b>
-              The  maximal  number  of  recipient addresses that any client is
+              The maximal number of recipient addresses  that  any  client  is
-              allowed to send to this service per  time  unit,  regardless  of
+              allowed  to  send  to  this service per time unit, regardless of
               whether or not Postfix actually accepts those recipients.
 
        <b><a href="postconf.5.html#smtpd_client_event_limit_exceptions">smtpd_client_event_limit_exceptions</a> ($<a href="postconf.5.html#mynetworks">mynetworks</a>)</b>
-              Clients  that  are excluded from smtpd_client_*_count/rate_limit
+              Clients that are excluded  from  smtpd_client_*_count/rate_limit
               restrictions.
 
        Available in Postfix version 2.3 and later:
 
        <b><a href="postconf.5.html#smtpd_client_new_tls_session_rate_limit">smtpd_client_new_tls_session_rate_limit</a> (0)</b>
-              The maximal number of new (i.e., uncached) TLS sessions  that  a
+              The  maximal  number of new (i.e., uncached) TLS sessions that a
               remote SMTP client is allowed to negotiate with this service per
               time unit.
 
@@ -953,29 +960,29 @@ SMTPD(8)                                                              SMTPD(8)
 
        <b><a href="postconf.5.html#smtpd_per_record_deadline">smtpd_per_record_deadline</a> (normal: no, <a href="STRESS_README.html">overload</a>: yes)</b>
               Change  the  behavior  of  the  <a href="postconf.5.html#smtpd_timeout">smtpd_timeout</a>  and  <a href="postconf.5.html#smtpd_starttls_timeout">smtpd_start</a>-
-              <a href="postconf.5.html#smtpd_starttls_timeout">tls_timeout</a>  time  limits,  from  a time limit per read or write
+              <a href="postconf.5.html#smtpd_starttls_timeout">tls_timeout</a> time limits, from a time limit  per  read  or  write
-              system call, to a time limit  to  send  or  receive  a  complete
+              system  call,  to  a  time  limit  to send or receive a complete
-              record  (an  SMTP command line, SMTP response line, SMTP message
+              record (an SMTP command line, SMTP response line,  SMTP  message
               content line, or TLS protocol message).
 
        Available in Postfix version 3.1 and later:
 
        <b><a href="postconf.5.html#smtpd_client_auth_rate_limit">smtpd_client_auth_rate_limit</a> (0)</b>
-              The maximal number of AUTH commands that any client  is  allowed
+              The  maximal  number of AUTH commands that any client is allowed
-              to  send to this service per time unit, regardless of whether or
+              to send to this service per time unit, regardless of whether  or
               not Postfix actually accepts those commands.
 
        Available in Postfix version 3.7 and later:
 
        <b><a href="postconf.5.html#smtpd_per_request_deadline">smtpd_per_request_deadline</a> (normal: no, <a href="STRESS_README.html">overload</a>: yes)</b>
               Change  the  behavior  of  the  <a href="postconf.5.html#smtpd_timeout">smtpd_timeout</a>  and  <a href="postconf.5.html#smtpd_starttls_timeout">smtpd_start</a>-
-              <a href="postconf.5.html#smtpd_starttls_timeout">tls_timeout</a>  time limits, from a time limit per plaintext or TLS
+              <a href="postconf.5.html#smtpd_starttls_timeout">tls_timeout</a> time limits, from a time limit per plaintext or  TLS
-              read or write call, to a combined time  limit  for  receiving  a
+              read  or  write  call,  to a combined time limit for receiving a
-              complete  SMTP request and for sending a complete SMTP response.
+              complete SMTP request and for sending a complete SMTP  response.
 
        <b><a href="postconf.5.html#smtpd_min_data_rate">smtpd_min_data_rate</a> (500)</b>
-              The minimum plaintext data transfer  rate  in  bytes/second  for
+              The  minimum  plaintext  data  transfer rate in bytes/second for
-              DATA   and  BDAT  requests,  when  deadlines  are  enabled  with
+              DATA  and  BDAT  requests,  when  deadlines  are  enabled   with
               <a href="postconf.5.html#smtpd_per_request_deadline">smtpd_per_request_deadline</a>.
 
        <b><a href="postconf.5.html#header_from_format">header_from_format</a> (standard)</b>
@@ -984,27 +991,27 @@ SMTPD(8)                                                              SMTPD(8)
        Available in Postfix version 3.8 and later:
 
        <b><a href="postconf.5.html#smtpd_client_ipv4_prefix_length">smtpd_client_ipv4_prefix_length</a> (32)</b>
-              Aggregate smtpd_client_*_count and  smtpd_client_*_rate  statis-
+              Aggregate  smtpd_client_*_count  and smtpd_client_*_rate statis-
               tics by IPv4 network blocks with the specified network prefix.
 
        <b><a href="postconf.5.html#smtpd_client_ipv6_prefix_length">smtpd_client_ipv6_prefix_length</a> (84)</b>
-              Aggregate  smtpd_client_*_count  and smtpd_client_*_rate statis-
+              Aggregate smtpd_client_*_count and  smtpd_client_*_rate  statis-
               tics by IPv6 network blocks with the specified network prefix.
 
        Available in Postfix 3.9, 3.8.1, 3.7.6, 3.6.10, 3.5.20 and later:
 
        <b><a href="postconf.5.html#smtpd_forbid_unauth_pipelining">smtpd_forbid_unauth_pipelining</a> (Postfix</b> &gt;<b>= 3.9: yes)</b>
-              Disconnect remote SMTP clients that violate <a href="https://tools.ietf.org/html/rfc2920">RFC 2920</a>  (or  5321)
+              Disconnect  remote  SMTP clients that violate <a href="https://tools.ietf.org/html/rfc2920">RFC 2920</a> (or 5321)
               command pipelining constraints.
 
        Available in Postfix 3.9, 3.8.4, 3.7.9, 3.6.13, 3.5.23 and later:
 
        <b><a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a> (Postfix</b> &gt;<b>= 3.9: normalize)</b>
-              Reject  or  restrict input lines from an SMTP client that end in
+              Reject or restrict input lines from an SMTP client that  end  in
               &lt;LF&gt; instead of the standard &lt;CR&gt;&lt;LF&gt;.
 
        <b><a href="postconf.5.html#smtpd_forbid_bare_newline_exclusions">smtpd_forbid_bare_newline_exclusions</a> ($<a href="postconf.5.html#mynetworks">mynetworks</a>)</b>
-              Exclude the  specified  clients  from  <a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a>
+              Exclude  the  specified  clients  from <a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a>
               enforcement.
 
        Available in Postfix 3.9, 3.8.5, 3.7.10, 3.6.14, 3.5.24 and later:
@@ -1014,55 +1021,55 @@ SMTPD(8)                                                              SMTPD(8)
               request with "<a href="postconf.5.html#smtpd_forbid_bare_newline">smtpd_forbid_bare_newline</a> = reject".
 
 <b><a name="tarpit_controls">TARPIT CONTROLS</a></b>
-       When a remote SMTP client makes errors, the  Postfix  SMTP  server  can
+       When  a  remote  SMTP  client makes errors, the Postfix SMTP server can
-       insert  delays  before  responding. This can help to slow down run-away
+       insert delays before responding. This can help to  slow  down  run-away
-       software.  The behavior is controlled by an error counter  that  counts
+       software.   The  behavior is controlled by an error counter that counts
        the number of errors within an SMTP session that a client makes without
        delivering mail.
 
        <b><a href="postconf.5.html#smtpd_error_sleep_time">smtpd_error_sleep_time</a> (1s)</b>
-              With Postfix version 2.1 and later:  the  SMTP  server  response
+              With  Postfix  version  2.1  and later: the SMTP server response
-              delay  after a client has made more than $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a>
+              delay after a client has made more than  $<a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a>
-              errors, and fewer than $<a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a>  errors,  without
+              errors,  and  fewer than $<a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> errors, without
               delivering mail.
 
        <b><a href="postconf.5.html#smtpd_soft_error_limit">smtpd_soft_error_limit</a> (10)</b>
-              The  number  of  errors  a remote SMTP client is allowed to make
+              The number of errors a remote SMTP client  is  allowed  to  make
-              without delivering mail before the  Postfix  SMTP  server  slows
+              without  delivering  mail  before  the Postfix SMTP server slows
               down all its responses.
 
        <b><a href="postconf.5.html#smtpd_hard_error_limit">smtpd_hard_error_limit</a> (normal: 20, <a href="STRESS_README.html">overload</a>: 1)</b>
-              The  maximal number of errors a remote SMTP client is allowed to
+              The maximal number of errors a remote SMTP client is allowed  to
               make without delivering mail.
 
        <b><a href="postconf.5.html#smtpd_junk_command_limit">smtpd_junk_command_limit</a> (normal: 100, <a href="STRESS_README.html">overload</a>: 1)</b>
-              The number of junk commands (NOOP, VRFY, ETRN or  RSET)  that  a
+              The  number  of  junk commands (NOOP, VRFY, ETRN or RSET) that a
-              remote  SMTP  client  can  send  before  the Postfix SMTP server
+              remote SMTP client can  send  before  the  Postfix  SMTP  server
               starts to increment the error counter with each junk command.
 
        Available in Postfix version 2.1 and later:
 
        <b><a href="postconf.5.html#smtpd_recipient_overshoot_limit">smtpd_recipient_overshoot_limit</a> (1000)</b>
-              The number of recipients that a remote SMTP client can  send  in
+              The  number  of recipients that a remote SMTP client can send in
               excess  of  the  limit  specified  with  $<a href="postconf.5.html#smtpd_recipient_limit">smtpd_recipient_limit</a>,
-              before the Postfix SMTP server increments the per-session  error
+              before  the Postfix SMTP server increments the per-session error
               count for each excess recipient.
 
 <b><a name="access_policy_delegation_controls">ACCESS POLICY DELEGATION CONTROLS</a></b>
-       As  of version 2.1, Postfix can be configured to delegate access policy
+       As of version 2.1, Postfix can be configured to delegate access  policy
-       decisions to an external server that runs  outside  Postfix.   See  the
+       decisions  to  an  external  server that runs outside Postfix.  See the
        file <a href="SMTPD_POLICY_README.html">SMTPD_POLICY_README</a> for more information.
 
        <b><a href="postconf.5.html#smtpd_policy_service_max_idle">smtpd_policy_service_max_idle</a> (300s)</b>
-              The  time after which an idle SMTPD policy service connection is
+              The time after which an idle SMTPD policy service connection  is
               closed.
 
        <b><a href="postconf.5.html#smtpd_policy_service_max_ttl">smtpd_policy_service_max_ttl</a> (1000s)</b>
-              The time after which an active SMTPD policy  service  connection
+              The  time  after which an active SMTPD policy service connection
               is closed.
 
        <b><a href="postconf.5.html#smtpd_policy_service_timeout">smtpd_policy_service_timeout</a> (100s)</b>
-              The  time limit for connecting to, writing to, or receiving from
+              The time limit for connecting to, writing to, or receiving  from
               a delegated SMTPD policy server.
 
        Available in Postfix version 3.0 and later:
@@ -1072,81 +1079,81 @@ SMTPD(8)                                                              SMTPD(8)
               The default action when an SMTPD policy service request fails.
 
        <b><a href="postconf.5.html#smtpd_policy_service_request_limit">smtpd_policy_service_request_limit</a> (0)</b>
-              The maximal number of requests per SMTPD policy service  connec-
+              The  maximal number of requests per SMTPD policy service connec-
               tion, or zero (no limit).
 
        <b><a href="postconf.5.html#smtpd_policy_service_try_limit">smtpd_policy_service_try_limit</a> (2)</b>
-              The  maximal  number of attempts to send an SMTPD policy service
+              The maximal number of attempts to send an SMTPD  policy  service
               request before giving up.
 
        <b><a href="postconf.5.html#smtpd_policy_service_retry_delay">smtpd_policy_service_retry_delay</a> (1s)</b>
-              The delay between attempts to resend a failed SMTPD policy  ser-
+              The  delay between attempts to resend a failed SMTPD policy ser-
               vice request.
 
        Available in Postfix version 3.1 and later:
 
        <b><a href="postconf.5.html#smtpd_policy_service_policy_context">smtpd_policy_service_policy_context</a> (empty)</b>
-              Optional  information  that the Postfix SMTP server specifies in
+              Optional information that the Postfix SMTP server  specifies  in
-              the "policy_context"  attribute  of  a  policy  service  request
+              the  "policy_context"  attribute  of  a  policy  service request
-              (originally,  to  share the same service endpoint among multiple
+              (originally, to share the same service endpoint  among  multiple
               <a href="postconf.5.html#check_policy_service">check_policy_service</a> clients).
 
 <b><a name="access_controls">ACCESS CONTROLS</a></b>
-       The <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a> document gives an introduction to all the  SMTP
+       The  <a href="SMTPD_ACCESS_README.html">SMTPD_ACCESS_README</a> document gives an introduction to all the SMTP
        server access control features.
 
        <b><a href="postconf.5.html#smtpd_delay_reject">smtpd_delay_reject</a> (yes)</b>
-              Wait    until    the   RCPT   TO   command   before   evaluating
+              Wait   until   the   RCPT   TO   command    before    evaluating
               $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>,     $<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>     and
               $<a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a>,  or  wait  until  the  ETRN  command
-              before      evaluating      $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>       and
+              before       evaluating      $<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a>      and
               $<a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a>.
 
        <b><a href="postconf.5.html#parent_domain_matches_subdomains">parent_domain_matches_subdomains</a> (see 'postconf -d' output)</b>
-              A  list of Postfix features where the pattern "example.com" also
+              A list of Postfix features where the pattern "example.com"  also
-              matches subdomains  of  example.com,  instead  of  requiring  an
+              matches  subdomains  of  example.com,  instead  of  requiring an
               explicit ".example.com" pattern.
 
        <b><a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> (empty)</b>
-              Optional  restrictions  that  the Postfix SMTP server applies in
+              Optional restrictions that the Postfix SMTP  server  applies  in
               the context of a client connection request.
 
        <b><a href="postconf.5.html#smtpd_helo_required">smtpd_helo_required</a> (no)</b>
-              Require that a remote SMTP client  introduces  itself  with  the
+              Require  that  a  remote  SMTP client introduces itself with the
-              HELO  or  EHLO  command before sending the MAIL command or other
+              HELO or EHLO command before sending the MAIL  command  or  other
               commands that require EHLO negotiation.
 
        <b><a href="postconf.5.html#smtpd_helo_restrictions">smtpd_helo_restrictions</a> (empty)</b>
-              Optional restrictions that the Postfix SMTP  server  applies  in
+              Optional  restrictions  that  the Postfix SMTP server applies in
               the context of a client HELO command.
 
        <b><a href="postconf.5.html#smtpd_sender_restrictions">smtpd_sender_restrictions</a> (empty)</b>
-              Optional  restrictions  that  the Postfix SMTP server applies in
+              Optional restrictions that the Postfix SMTP  server  applies  in
               the context of a client MAIL FROM command.
 
        <b><a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a> (see 'postconf -d' output)</b>
-              Optional restrictions that the Postfix SMTP  server  applies  in
+              Optional  restrictions  that  the Postfix SMTP server applies in
-              the    context    of   a   client   RCPT   TO   command,   after
+              the   context   of   a   client   RCPT   TO    command,    after
               <a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a>.
 
        <b><a href="postconf.5.html#smtpd_etrn_restrictions">smtpd_etrn_restrictions</a> (empty)</b>
-              Optional restrictions that the Postfix SMTP  server  applies  in
+              Optional  restrictions  that  the Postfix SMTP server applies in
               the context of a client ETRN command.
 
        <b><a href="postconf.5.html#allow_untrusted_routing">allow_untrusted_routing</a> (no)</b>
-              Forward       mail       with      sender-specified      routing
+              Forward      mail      with       sender-specified       routing
-              (user[@%!]remote[@%!]site) from untrusted  clients  to  destina-
+              (user[@%!]remote[@%!]site)  from  untrusted  clients to destina-
               tions matching $<a href="postconf.5.html#relay_domains">relay_domains</a>.
 
        <b><a href="postconf.5.html#smtpd_restriction_classes">smtpd_restriction_classes</a> (empty)</b>
               User-defined aliases for groups of access restrictions.
 
        <b><a href="postconf.5.html#smtpd_null_access_lookup_key">smtpd_null_access_lookup_key</a> (</b>&lt;&gt;<b>)</b>
-              The  lookup  key  to be used in SMTP <a href="access.5.html"><b>access</b>(5)</a> tables instead of
+              The lookup key to be used in SMTP <a href="access.5.html"><b>access</b>(5)</a>  tables  instead  of
               the null sender address.
 
        <b><a href="postconf.5.html#permit_mx_backup_networks">permit_mx_backup_networks</a> (empty)</b>
-              Restrict the use of the <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> SMTP access feature  to
+              Restrict  the use of the <a href="postconf.5.html#permit_mx_backup">permit_mx_backup</a> SMTP access feature to
               only domains whose primary MX hosts match the listed networks.
 
        Available in Postfix version 2.0 and later:
@@ -1156,19 +1163,19 @@ SMTPD(8)                                                              SMTPD(8)
               applies in the context of the SMTP DATA command.
 
        <b><a href="postconf.5.html#smtpd_expansion_filter">smtpd_expansion_filter</a> (see 'postconf -d' output)</b>
-              What characters are allowed in $name  expansions  of  RBL  reply
+              What  characters  are  allowed  in $name expansions of RBL reply
               templates.
 
        Available in Postfix version 2.1 and later:
 
        <b><a href="postconf.5.html#smtpd_reject_unlisted_sender">smtpd_reject_unlisted_sender</a> (no)</b>
-              Request  that  the Postfix SMTP server rejects mail from unknown
+              Request that the Postfix SMTP server rejects mail  from  unknown
-              sender addresses, even when no  explicit  <a href="postconf.5.html#reject_unlisted_sender">reject_unlisted_sender</a>
+              sender  addresses,  even when no explicit <a href="postconf.5.html#reject_unlisted_sender">reject_unlisted_sender</a>
               access restriction is specified.
 
        <b><a href="postconf.5.html#smtpd_reject_unlisted_recipient">smtpd_reject_unlisted_recipient</a> (yes)</b>
-              Request  that  the  Postfix SMTP server rejects mail for unknown
+              Request that the Postfix SMTP server rejects  mail  for  unknown
-              recipient     addresses,     even     when      no      explicit
+              recipient      addresses,      even     when     no     explicit
               <a href="postconf.5.html#reject_unlisted_recipient">reject_unlisted_recipient</a> access restriction is specified.
 
        Available in Postfix version 2.2 and later:
@@ -1182,17 +1189,17 @@ SMTPD(8)                                                              SMTPD(8)
        <b><a href="postconf.5.html#smtpd_relay_restrictions">smtpd_relay_restrictions</a> (<a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>, <a href="postconf.5.html#permit_sasl_authenticated">permit_sasl_authenticated</a>,</b>
        <b><a href="postconf.5.html#defer_unauth_destination">defer_unauth_destination</a>)</b>
               Access restrictions for mail relay control that the Postfix SMTP
-              server  applies  in  the  context of the RCPT TO command, before
+              server applies in the context of the  RCPT  TO  command,  before
               <a href="postconf.5.html#smtpd_recipient_restrictions">smtpd_recipient_restrictions</a>.
 
 <b><a name="sender_and_recipient_address_verification_controls">SENDER AND RECIPIENT ADDRESS VERIFICATION CONTROLS</a></b>
-       Postfix version 2.1 introduces sender and recipient  address  verifica-
+       Postfix  version  2.1 introduces sender and recipient address verifica-
        tion.  This feature is implemented by sending probe email messages that
        are  not  actually  delivered.   This  feature  is  requested  via  the
-       <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>    and    <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a>   access
+       <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>   and    <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a>    access
-       restrictions.  The status of verification probes is maintained  by  the
+       restrictions.   The  status of verification probes is maintained by the
-       <a href="verify.8.html"><b>verify</b>(8)</a>  server.  See the file <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> for infor-
+       <a href="verify.8.html"><b>verify</b>(8)</a> server.  See the file <a href="ADDRESS_VERIFICATION_README.html">ADDRESS_VERIFICATION_README</a> for  infor-
-       mation about how to configure and operate the Postfix  sender/recipient
+       mation  about how to configure and operate the Postfix sender/recipient
        address verification service.
 
        <b><a href="postconf.5.html#address_verify_poll_count">address_verify_poll_count</a> (normal: 3, <a href="STRESS_README.html">overload</a>: 1)</b>
@@ -1204,7 +1211,7 @@ SMTPD(8)                                                              SMTPD(8)
               fication request in progress.
 
        <b><a href="postconf.5.html#address_verify_sender">address_verify_sender</a> ($<a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a>)</b>
-              The  sender address to use in address verification probes; prior
+              The sender address to use in address verification probes;  prior
               to Postfix 2.5 the default was "postmaster".
 
        <b><a href="postconf.5.html#unverified_sender_reject_code">unverified_sender_reject_code</a> (450)</b>
@@ -1212,18 +1219,18 @@ SMTPD(8)                                                              SMTPD(8)
               address is rejected by the <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a> restriction.
 
        <b><a href="postconf.5.html#unverified_recipient_reject_code">unverified_recipient_reject_code</a> (450)</b>
-              The numerical Postfix SMTP  server  response  when  a  recipient
+              The  numerical  Postfix  SMTP  server  response when a recipient
-              address  is rejected by the <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a> restric-
+              address is rejected by the <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a>  restric-
               tion.
 
        Available in Postfix version 2.6 and later:
 
        <b><a href="postconf.5.html#unverified_sender_defer_code">unverified_sender_defer_code</a> (450)</b>
-              The numerical Postfix SMTP server response code  when  a  sender
+              The  numerical  Postfix  SMTP server response code when a sender
               address probe fails due to a temporary error condition.
 
        <b><a href="postconf.5.html#unverified_recipient_defer_code">unverified_recipient_defer_code</a> (450)</b>
-              The  numerical  Postfix  SMTP  server  response when a recipient
+              The numerical Postfix SMTP  server  response  when  a  recipient
               address probe fails due to a temporary error condition.
 
        <b><a href="postconf.5.html#unverified_sender_reject_reason">unverified_sender_reject_reason</a> (empty)</b>
@@ -1235,17 +1242,17 @@ SMTPD(8)                                                              SMTPD(8)
               <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipient</a>.
 
        <b><a href="postconf.5.html#unverified_sender_tempfail_action">unverified_sender_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
-              The Postfix SMTP server's action  when  <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>
+              The  Postfix  SMTP server's action when <a href="postconf.5.html#reject_unverified_sender">reject_unverified_sender</a>
               fails due to a temporary error condition.
 
        <b><a href="postconf.5.html#unverified_recipient_tempfail_action">unverified_recipient_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
-              The  Postfix SMTP server's action when <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipi</a>-
+              The Postfix SMTP server's action when  <a href="postconf.5.html#reject_unverified_recipient">reject_unverified_recipi</a>-
               <a href="postconf.5.html#reject_unverified_recipient">ent</a> fails due to a temporary error condition.
 
        Available with Postfix 2.9 and later:
 
        <b><a href="postconf.5.html#address_verify_sender_ttl">address_verify_sender_ttl</a> (0s)</b>
-              The time  between  changes  in  the  time-dependent  portion  of
+              The  time  between  changes  in  the  time-dependent  portion of
               address verification probe sender addresses.
 
 <b><a name="access_control_responses">ACCESS CONTROL RESPONSES</a></b>
@@ -1257,36 +1264,36 @@ SMTPD(8)                                                              SMTPD(8)
               map "reject" action.
 
        <b><a href="postconf.5.html#defer_code">defer_code</a> (450)</b>
-              The  numerical  Postfix  SMTP server response code when a remote
+              The numerical Postfix SMTP server response code  when  a  remote
               SMTP client request is rejected by the "defer" restriction.
 
        <b><a href="postconf.5.html#invalid_hostname_reject_code">invalid_hostname_reject_code</a> (501)</b>
-              The numerical Postfix SMTP server response code when the  client
+              The  numerical Postfix SMTP server response code when the client
-              HELO   or   EHLO   command   parameter   is   rejected   by  the
+              HELO  or   EHLO   command   parameter   is   rejected   by   the
               <a href="postconf.5.html#reject_invalid_helo_hostname">reject_invalid_helo_hostname</a> restriction.
 
        <b><a href="postconf.5.html#maps_rbl_reject_code">maps_rbl_reject_code</a> (554)</b>
-              The numerical Postfix SMTP server response code  when  a  remote
+              The  numerical  Postfix  SMTP server response code when a remote
-              SMTP   client  request  is  blocked  by  the  <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a>,
+              SMTP  client  request  is  blocked  by  the   <a href="postconf.5.html#reject_rbl_client">reject_rbl_client</a>,
               <a href="postconf.5.html#reject_rhsbl_client">reject_rhsbl_client</a>,                <a href="postconf.5.html#reject_rhsbl_reverse_client">reject_rhsbl_reverse_client</a>,
               <a href="postconf.5.html#reject_rhsbl_sender">reject_rhsbl_sender</a> or <a href="postconf.5.html#reject_rhsbl_recipient">reject_rhsbl_recipient</a> restriction.
 
        <b><a href="postconf.5.html#non_fqdn_reject_code">non_fqdn_reject_code</a> (504)</b>
-              The  numerical  Postfix  SMTP  server  reply  code when a client
+              The numerical Postfix SMTP  server  reply  code  when  a  client
-              request  is  rejected  by   the   <a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a>,
+              request   is   rejected  by  the  <a href="postconf.5.html#reject_non_fqdn_helo_hostname">reject_non_fqdn_helo_hostname</a>,
               <a href="postconf.5.html#reject_non_fqdn_sender">reject_non_fqdn_sender</a> or <a href="postconf.5.html#reject_non_fqdn_recipient">reject_non_fqdn_recipient</a> restriction.
 
        <b><a href="postconf.5.html#plaintext_reject_code">plaintext_reject_code</a> (450)</b>
-              The numerical Postfix SMTP server response code when  a  request
+              The  numerical  Postfix SMTP server response code when a request
               is rejected by the <b><a href="postconf.5.html#reject_plaintext_session">reject_plaintext_session</a></b> restriction.
 
        <b><a href="postconf.5.html#reject_code">reject_code</a> (554)</b>
-              The  numerical  Postfix  SMTP server response code when a remote
+              The numerical Postfix SMTP server response code  when  a  remote
               SMTP client request is rejected by the "reject" restriction.
 
        <b><a href="postconf.5.html#relay_domains_reject_code">relay_domains_reject_code</a> (554)</b>
-              The numerical Postfix SMTP server response code  when  a  client
+              The  numerical  Postfix  SMTP server response code when a client
-              request  is  rejected by the <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a> recipient
+              request is rejected by the  <a href="postconf.5.html#reject_unauth_destination">reject_unauth_destination</a>  recipient
               restriction.
 
        <b><a href="postconf.5.html#unknown_address_reject_code">unknown_address_reject_code</a> (450)</b>
@@ -1294,24 +1301,24 @@ SMTPD(8)                                                              SMTPD(8)
               a sender or recipient address because its domain is unknown.
 
        <b><a href="postconf.5.html#unknown_client_reject_code">unknown_client_reject_code</a> (450)</b>
-              The  numerical  Postfix  SMTP server response code when a client
+              The numerical Postfix SMTP server response code  when  a  client
-              without valid address  &lt;=&gt;  name  mapping  is  rejected  by  the
+              without  valid  address  &lt;=&gt;  name  mapping  is  rejected by the
               <a href="postconf.5.html#reject_unknown_client_hostname">reject_unknown_client_hostname</a> restriction.
 
        <b><a href="postconf.5.html#unknown_hostname_reject_code">unknown_hostname_reject_code</a> (450)</b>
-              The  numerical  Postfix SMTP server response code when the host-
+              The numerical Postfix SMTP server response code when  the  host-
-              name specified with the HELO or EHLO command is rejected by  the
+              name  specified with the HELO or EHLO command is rejected by the
               <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_hostname</a> restriction.
 
        Available in Postfix version 2.0 and later:
 
        <b><a href="postconf.5.html#default_rbl_reply">default_rbl_reply</a> (see 'postconf -d' output)</b>
-              The  default Postfix SMTP server response template for a request
+              The default Postfix SMTP server response template for a  request
               that is rejected by an RBL-based restriction.
 
        <b><a href="postconf.5.html#multi_recipient_bounce_reject_code">multi_recipient_bounce_reject_code</a> (550)</b>
-              The numerical Postfix SMTP server response code  when  a  remote
+              The  numerical  Postfix  SMTP server response code when a remote
-              SMTP  client  request  is  blocked  by  the <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipi</a>-
+              SMTP client  request  is  blocked  by  the  <a href="postconf.5.html#reject_multi_recipient_bounce">reject_multi_recipi</a>-
               <a href="postconf.5.html#reject_multi_recipient_bounce">ent_bounce</a> restriction.
 
        <b><a href="postconf.5.html#rbl_reply_maps">rbl_reply_maps</a> (empty)</b>
@@ -1321,52 +1328,52 @@ SMTPD(8)                                                              SMTPD(8)
 
        <b><a href="postconf.5.html#access_map_defer_code">access_map_defer_code</a> (450)</b>
               The numerical Postfix SMTP server response code for an <a href="access.5.html"><b>access</b>(5)</a>
-              map    "defer"    action,    including    "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>"   or
+              map   "defer"    action,    including    "<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>"    or
               "<a href="postconf.5.html#defer_if_reject">defer_if_reject</a>".
 
        <b><a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a> (<a href="postconf.5.html#defer_if_permit">defer_if_permit</a>)</b>
-              The Postfix SMTP server's action when a reject-type  restriction
+              The  Postfix SMTP server's action when a reject-type restriction
               fails due to a temporary error condition.
 
        <b><a href="postconf.5.html#unknown_helo_hostname_tempfail_action">unknown_helo_hostname_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
-              The  Postfix SMTP server's action when <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_host</a>-
+              The Postfix SMTP server's action when  <a href="postconf.5.html#reject_unknown_helo_hostname">reject_unknown_helo_host</a>-
               <a href="postconf.5.html#reject_unknown_helo_hostname">name</a> fails due to a temporary error condition.
 
        <b><a href="postconf.5.html#unknown_address_tempfail_action">unknown_address_tempfail_action</a> ($<a href="postconf.5.html#reject_tempfail_action">reject_tempfail_action</a>)</b>
-              The      Postfix      SMTP      server's       action       when
+              The       Postfix       SMTP      server's      action      when
-              <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a>  or <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
+              <a href="postconf.5.html#reject_unknown_sender_domain">reject_unknown_sender_domain</a> or  <a href="postconf.5.html#reject_unknown_recipient_domain">reject_unknown_recipient_domain</a>
               fail due to a temporary error condition.
 
 <b><a name="miscellaneous_controls">MISCELLANEOUS CONTROLS</a></b>
        <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
-              The default location of the Postfix <a href="postconf.5.html">main.cf</a> and  <a href="master.5.html">master.cf</a>  con-
+              The  default  location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> con-
               figuration files.
 
        <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
-              How  much  time  a  Postfix  daemon process may take to handle a
+              How much time a Postfix daemon process  may  take  to  handle  a
               request before it is terminated by a built-in watchdog timer.
 
        <b><a href="postconf.5.html#command_directory">command_directory</a> (see 'postconf -d' output)</b>
               The location of all postfix administrative commands.
 
        <b><a href="postconf.5.html#double_bounce_sender">double_bounce_sender</a> (double-bounce)</b>
-              The sender address of postmaster notifications that  are  gener-
+              The  sender  address of postmaster notifications that are gener-
               ated by the mail system.
 
        <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
-              The  time  limit  for  sending  or receiving information over an
+              The time limit for sending  or  receiving  information  over  an
               internal communication channel.
 
        <b><a href="postconf.5.html#mail_name">mail_name</a> (Postfix)</b>
-              The mail system name that is displayed in Received: headers,  in
+              The  mail system name that is displayed in Received: headers, in
               the SMTP greeting banner, and in bounced mail.
 
        <b><a href="postconf.5.html#mail_owner">mail_owner</a> (postfix)</b>
-              The  UNIX  system  account  that owns the Postfix queue and most
+              The UNIX system account that owns the  Postfix  queue  and  most
               Postfix daemon processes.
 
        <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
-              The maximum amount of time that an idle Postfix  daemon  process
+              The  maximum  amount of time that an idle Postfix daemon process
               waits for an incoming connection before terminating voluntarily.
 
        <b><a href="postconf.5.html#max_use">max_use</a> (100)</b>
@@ -1377,11 +1384,11 @@ SMTPD(8)                                                              SMTPD(8)
               The internet hostname of this mail system.
 
        <b><a href="postconf.5.html#mynetworks">mynetworks</a> (see 'postconf -d' output)</b>
-              The  list of "trusted" remote SMTP clients that have more privi-
+              The list of "trusted" remote SMTP clients that have more  privi-
               leges than "strangers".
 
        <b><a href="postconf.5.html#myorigin">myorigin</a> ($<a href="postconf.5.html#myhostname">myhostname</a>)</b>
-              The domain name that locally-posted mail appears to  come  from,
+              The  domain  name that locally-posted mail appears to come from,
               and that locally posted mail is delivered to.
 
        <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
@@ -1394,24 +1401,24 @@ SMTPD(8)                                                              SMTPD(8)
               The location of the Postfix top-level queue directory.
 
        <b><a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a> (empty)</b>
-              The  set of characters that can separate an email address local-
+              The set of characters that can separate an email address  local-
               part, user name, or a .forward file name from its extension.
 
        <b><a href="postconf.5.html#smtpd_banner">smtpd_banner</a> ($<a href="postconf.5.html#myhostname">myhostname</a> ESMTP $<a href="postconf.5.html#mail_name">mail_name</a>)</b>
-              The text that follows the 220 status code in the  SMTP  greeting
+              The  text  that follows the 220 status code in the SMTP greeting
               banner.
 
        <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
               The syslog facility of Postfix logging.
 
        <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
-              A  prefix  that  is  prepended  to  the  process  name in syslog
+              A prefix that  is  prepended  to  the  process  name  in  syslog
               records, so that, for example, "smtpd" becomes "prefix/smtpd".
 
        Available in Postfix version 2.2 and later:
 
        <b><a href="postconf.5.html#smtpd_forbidden_commands">smtpd_forbidden_commands</a> (CONNECT GET POST <a href="regexp_table.5.html">regexp</a>:{{/^[^A-Z]/ Bogus}})</b>
-              List of commands that cause the Postfix SMTP server  to  immedi-
+              List  of  commands that cause the Postfix SMTP server to immedi-
               ately terminate the session with a 221 code.
 
        Available in Postfix version 2.5 and later:
@@ -1428,13 +1435,13 @@ SMTPD(8)                                                              SMTPD(8)
        Available in Postfix 3.4 and later:
 
        <b><a href="postconf.5.html#smtpd_reject_footer_maps">smtpd_reject_footer_maps</a> (empty)</b>
-              Lookup tables, indexed by the complete Postfix SMTP  server  4xx
+              Lookup  tables,  indexed by the complete Postfix SMTP server 4xx
               or 5xx response, with reject footer templates.
 
        Available in Postfix 3.10 and later:
 
        <b><a href="postconf.5.html#smtpd_hide_client_session">smtpd_hide_client_session</a> (no)</b>
-              Do  not  include  SMTP client session information in the Postfix
+              Do not include SMTP client session information  in  the  Postfix
               SMTP server's Received: message header.
 
 <b><a name="see_also">SEE ALSO</a></b>

postfix/makedefs

@@ -979,7 +979,7 @@ CCARGS="$CCARGS -DSNAPSHOT"
 
 # Non-production: needs thorough testing, or major changes are still
 # needed before the code stabilizes.
-#CCARGS="$CCARGS -DNONPROD"
+CCARGS="$CCARGS -DNONPROD"
 
 # Workaround: prepend Postfix include files before other include files.
 CCARGS="-I. -I../../include $CCARGS"

postfix/man/man1/sendmail.1

@@ -158,10 +158,28 @@ Delivery status notification control. Specify either a
 comma\-separated list with one or more of \fBfailure\fR (send
 notification when delivery fails), \fBdelay\fR (send
 notification when delivery is delayed), or \fBsuccess\fR
-(send notification when the message is delivered); or specify
+(send notification after the message is delivered); or specify
 \fBnever\fR (don't send any notifications at all).
 
 This feature is available in Postfix 2.3 and later.
+.IP "\fB\-O requiretls"
+When delivering a message to an SMTP or LMTP server, the
+connection must use TLS with a verified server certificate,
+and the server must support REQUIRETLS. Try multiple servers if
+possible, and return the message as undeliverable when these
+requirements were not satisfied with any of the servers that
+were tried. The "requiretls" option value is case\-insensitive.
+
+This feature is available in Postfix 3.10 and later.
+.IP "\fB\-O smtputf8"
+When delivering a message to an SMTP or LMTP server, the server
+must support SMTPUTF8. Try multiple servers if possible, and
+return the message as undeliverable when a message contains an
+UTF8 envelope address or message header, but SMTPUTF8 was not
+supported by any of the servers that were tried. The "smtputf8"
+option value is case\-insensitive.
+
+This feature is available in Postfix 3.10 and later.
 .IP "\fB\-n\fR (ignored)"
 Backwards compatibility.
 .IP "\fB\-oA\fIalias_database\fR"
@@ -462,6 +480,11 @@ these directories belong to additional Postfix instances that share
 the Postfix executable files and documentation with the default
 Postfix instance, and that are started, stopped, etc., together
 with the default Postfix instance.
+.PP
+Postfix 3.10 and later:
+.IP "\fBrequiretls_enable (yes)\fR"
+Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+8689.
 .SH "FILES"
 .na
 .nf

postfix/man/man5/postconf.5

@@ -3136,6 +3136,11 @@ The LMTP\-specific version of the smtp_dns_support_level
 configuration parameter.  See there for details.
 .PP
 This feature is available in Postfix 2.11 and later.
+.SH lmtp_enforce_requiretls (default: empty)
+The LMTP\-specific version of the smtp_enforce_requiretls
+configuration parameter. See there for details.
+.PP
+This feature is available in Postfix >= 3.11.
 .SH lmtp_enforce_tls (default: no)
 The LMTP\-specific version of the smtp_enforce_tls configuration
 parameter.  See there for details.
@@ -5046,6 +5051,10 @@ postscreen_access_list
 .IP "Postfix version 3.0 and later"
 smtpd_client_event_limit_exceptions
 .br
+.IP "Postfix version 3.11 and later"
+smtp_enforce_requiretls,
+lmtp_enforce_requiretls
+.br
 .br
 .SH permit_mx_backup_networks (default: empty)
 Restrict the use of the permit_mx_backup SMTP access feature to
@@ -6600,6 +6609,28 @@ Require that a \fBlocal\fR(8) recipient's home directory exists
 before mail delivery is attempted. By default this test is disabled.
 It can be useful for environments that import home directories to
 the mail server (IMPORTING HOME DIRECTORIES IS NOT RECOMMENDED).
+.SH requiretls_enable (default: yes)
+Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+8689. By issuing this verb in the "MAIL FROM" command, a sender
+specifies that a message must be delivered over TLS connections
+with a verified server certificate, to a server that announces
+"REQUIRETLS" support. This corresponds to the Postfix SMTP client
+TLS security levels "secure", "verify", "fingerprint", dane\-only,
+or opportunistic "dane", with a successful certificate match. The
+Postfix SMTP client will try one or more servers, controlled with
+the smtp_mx_address_limit parameter, until it finds a server that
+satisfies requirements. Otherwise, Postfix returns the message as
+undeliverable.
+.PP
+Notes:
+.IP \(bu
+REQUIRETLS enforcement is controlled with smtp_enforce_requiretls
+or lmtp_enforce_requiretls.
+.IP \(bu
+REQUIRETLS overrides "TLS\-Required: no".
+.br
+.PP
+This feature is available in Postfix >= 3.11.
 .SH reset_owner_alias (default: no)
 Reset the \fBlocal\fR(8) delivery agent's idea of the owner\-alias
 attribute, when delivering mail to a child alias that does not have
@@ -7534,6 +7565,77 @@ reasonably\-modern DNS \fBresolver\fR(3) library that implements the
 RES_USE_DNSSEC and RES_USE_EDNS0 resolver options.
 .PP
 This feature is available in Postfix 2.11 and later.
+.SH smtp_enforce_requiretls (default: empty)
+An optional list of next\-hop destinations that the Postfix
+SMTP/LMTP client will enforce REQUIRETLS for, when a message was
+received with the REQUIRETLS option: the next\-hop server must offer
+a matching TLS server certificate, and the server must announce
+REQUIRETLS support). Such a message will be returned to the sender
+if some REQUIRETLS requirement cannot be satisfied. These "hard"
+REQUIRETLS failures are logged as "REQUIRETLS failure".
+.PP
+Other messages that were received with the REQUIRETLS option
+will be delivered with REQUIRETLS if possible. If not, a message
+will be delivered as if it was received without the REQUIRETLS
+option. This allows a mail sending site to discover when REQUIRETLS
+can be enforced, without disrupting email deliveries. These "soft"
+REQUIRETLS failures are logged with "REQUIRETLS Debug".
+.PP
+On a perimeter MTA, it can make sense to turn off REQUIRETLS
+enforcement, or even to turn off REQUIRETLS support, when delivering
+a message to an internal destination. The internal servers may not
+support REQUIRETLS, and their connections may be secured with means
+other than DANE, STS, and the like.
+.PP
+The supported syntax differs with SMTP and LMTP:
+.IP \(bu
+With SMTP, specify a list of next\-hop domain names (without
+the ":port" or ":service" suffix), "/file/name" patterns or
+"type:table" lookup tables, separated by commas and/or whitespace.
+Continue long lines by starting the next line with whitespace. A
+"/file/name" pattern is replaced by its contents.  A "type:table"
+lookup table is matched when a domain appears as lookup key. Specify
+"!pattern" to exclude a domain.
+.IP \(bu
+With LMTP, specify list of domain names (without the "inet":
+prefix, or  ":port" or ":service" suffix), or UNIX\-domain socket
+"/path/name" (without the "unix:" prefix), or "type:table" lookup
+tables, separated by commas and/or whitespace. Continue long lines
+by starting the next line with whitespace. A "type:table" lookup
+table is matched when a domain appears as lookup key. Specify
+"!pattern" to exclude a domain or socket path.
+.br
+.PP
+Specify the form ".domain" to match any name ending in ".domain".
+To change this behavior, list "smtp_enforce_requiretls" or
+"lmtp_enforce_requiretls" in the parent_domain_matches_subdomains
+parameter value.
+.PP
+SMTP Examples:
+.PP
+.nf
+.na
+# Enforce REQUIRETLS for SMTP with selected next\-hop domains.
+smtp_enforce_requiretls = example.com, foo.example
+.br
+# Enforce REQUIRETLS for SMTP with all but a few next\-hop domains.
+smtp_enforce_requiretls = !foo.example, static:all
+.fi
+.ad
+.PP
+LMTP examples:
+.PP
+.nf
+.na
+# Don't enforce REQUIRETLS
+lmtp_enforce_requiretls =
+.br
+# Enforce REQUIRETLS for specific destinations.
+lmtp_enforce_requiretls = /path/to/socket, message\-store.example
+.fi
+.ad
+.PP
+This feature is available in Postfix >= 3.11.
 .SH smtp_enforce_tls (default: no)
 Enforcement mode: require that remote SMTP servers use TLS
 encryption, and never send mail in the clear.  This also requires
@@ -14522,6 +14624,8 @@ If a message contains a "TLS\-Required: no" header, then Postfix
 will add that header to a delivery status notification for that
 message.
 .PP
+Note: REQUIRETLS overrides "TLS\-Required: no".
+.PP
 This feature is available in Postfix >= 3.10.
 .SH tls_server_sni_maps (default: empty)
 Optional lookup tables that map names received from remote SMTP

postfix/man/man8/pipe.8

@@ -294,6 +294,14 @@ expands to as many command\-line arguments as there are recipients.
 .sp
 This information is modified by the \fBhqu\fR flags for quoting
 and case folding.
+.IP \fB${requiretls}\fR
+This feature should be used with content filters that pass
+filtered mail to the Postfix sendmail(1) command. The macro
+expands to the sendmail(1) command\-line option \fB\-Orequiretls\fR
+if the sender requested REQUIRETLS, otherwise it expands to
+\fB\-Onoop\fR.
+.sp
+This feature is available as of Postfix 3.10.
 .IP \fB${sasl_method}\fR
 This macro expands to the name of the SASL authentication
 mechanism in the AUTH command when the Postfix SMTP server

postfix/man/man8/smtp.8

@@ -190,7 +190,7 @@ RFC 5321 (SMTP protocol)
 RFC 6531 (Internationalized SMTP)
 RFC 6533 (Internationalized Delivery Status Notifications)
 RFC 7672 (SMTP security via opportunistic DANE TLS)
-RFC 8689 (TLS\-Required message header)
+RFC 8689 (SMTP REQUIRETLS extension)
 .SH DIAGNOSTICS
 .ad
 .fi
@@ -485,7 +485,7 @@ Available in Postfix version 3.9 and later:
 .IP "\fBsmtp_sasl_password_result_delimiter (:)\fR"
 The delimiter between username and password in sasl_passwd_maps lookup
 results.
-.SH "STARTTLS SUPPORT CONTROLS"
+.SH "TLS SUPPORT CONTROLS"
 .na
 .nf
 .ad
@@ -687,7 +687,16 @@ sessions.
 .IP "\fBtls_required_enable (yes)\fR"
 Enable support for the "TLS\-Required: no" message header, defined
 in RFC 8689.
-.SH "OBSOLETE STARTTLS CONTROLS"
+.IP "\fBrequiretls_enable (yes)\fR"
+Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+8689.
+.IP "\fBsmtp_enforce_requiretls (empty)\fR"
+An optional list of next\-hop destinations that the Postfix
+SMTP/LMTP client will enforce REQUIRETLS for, when a message was
+received with the REQUIRETLS option: the next\-hop server must offer
+a matching TLS server certificate, and the server must announce
+REQUIRETLS support).
+.SH "OBSOLETE TLS CONTROLS"
 .na
 .nf
 .ad

postfix/man/man8/smtpd.8

@@ -67,6 +67,7 @@ RFC 5321 (SMTP protocol)
 RFC 6531 (Internationalized SMTP)
 RFC 6533 (Internationalized Delivery Status Notifications)
 RFC 7505 ("Null MX" No Service Resource Record)
+RFC 8689 (SMTP REQUIRETLS extension)
 .SH DIAGNOSTICS
 .ad
 .fi
@@ -402,7 +403,7 @@ Available in Postfix 3.6 and later:
 .IP "\fBsmtpd_sasl_mechanism_filter (!external, static:rest)\fR"
 If non\-empty, a filter for the SASL mechanism names that the
 Postfix SMTP server will announce in the EHLO response.
-.SH "STARTTLS SUPPORT CONTROLS"
+.SH "TLS SUPPORT CONTROLS"
 .na
 .nf
 .ad
@@ -578,7 +579,12 @@ Available in Postfix version 3.9 and later:
 Request that remote SMTP clients send an RFC7250 raw public key
 instead of an X.509 certificate, when asking for or requiring client
 authentication.
-.SH "OBSOLETE STARTTLS CONTROLS"
+.PP
+Available in Postfix version 3.10 and later:
+.IP "\fBrequiretls_enable (yes)\fR"
+Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+8689.
+.SH "OBSOLETE TLS CONTROLS"
 .na
 .nf
 .ad

postfix/mantools/postlink

@@ -1188,6 +1188,10 @@ while (<>) {
     s;\bignore_srv_lookup_error\b;<a href="postconf.5.html#ignore_srv_lookup_error">$&</a>;g;
 
     s;\btls_required_enable\b;<a href="postconf.5.html#tls_required_enable">$&</a>;g;
+    s;\brequiretls_enable\b;<a href="postconf.5.html#requiretls_enable">$&</a>;g;
+    s;\bsmtp_enforce_requiretls\b;<a href="postconf.5.html#smtp_enforce_requiretls">$&</a>;g;
+    s;\blmtp_enforce_requiretls\b;<a href="postconf.5.html#lmtp_enforce_requiretls">$&</a>;g;
+
     s;\bfull_name_encoding_charset\b;<a href="postconf.5.html#full_name_encoding_charset">$&</a>;g;
     s;\bsmtpd_hide_client_session\b;<a href="postconf.5.html#smtpd_hide_client_session">$&</a>;g;
 

postfix/proto/postconf.proto

@@ -3374,6 +3374,13 @@ postscreen_access_list
 smtpd_client_event_limit_exceptions
 </dd>
 
+<dt> Postfix version 3.11 and later </dt>
+
+<dd>
+smtp_enforce_requiretls,
+lmtp_enforce_requiretls
+</dd>
+
 </dl>
 
 %PARAM propagate_unmatched_extensions canonical, virtual
@@ -19608,12 +19615,124 @@ in RFC 8689. By adding this header to a message, a sender requests
 no enforcement of TLS policy. This limits the Postfix SMTP client
 TLS security level to "may", that is, do not verify remote SMTP
 server certificates, and fall back to plaintext if TLS is unavailable.
-If a message contains a "TLS-Required: no" header, then Postfix
+If a message contains a "TLS-Required: no" header, then Postfix 
-will add that header to a delivery status notification for that
+will add that header to a delivery status notification for that 
 message. </p>
 
+<p> Note: REQUIRETLS overrides "TLS-Required: no". </p>
+
 <p> This feature is available in Postfix &ge; 3.10. </p>
 
+%PARAM requiretls_enable yes
+
+<p> Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+8689. By issuing this verb in the "MAIL FROM" command, a sender
+specifies that a message must be delivered over TLS connections
+with a verified server certificate, to a server that announces
+"REQUIRETLS" support. This corresponds to the Postfix SMTP client
+TLS security levels "secure", "verify", "fingerprint", dane-only,
+or opportunistic "dane", with a successful certificate match. The
+Postfix SMTP client will try one or more servers, controlled with
+the smtp_mx_address_limit parameter, until it finds a server that
+satisfies requirements. Otherwise, Postfix returns the message as
+undeliverable. </p>
+
+<p> Notes: </p>
+
+<ul>
+
+<li> <p> REQUIRETLS enforcement is controlled with smtp_enforce_requiretls
+or lmtp_enforce_requiretls. </p>
+
+<li> <p> REQUIRETLS overrides "TLS-Required: no". </p>
+
+</ul>
+
+<p> This feature is available in Postfix &ge; 3.11. </p>
+
+%PARAM smtp_enforce_requiretls empty
+
+<p> An optional list of next-hop destinations that the Postfix
+SMTP/LMTP client will enforce REQUIRETLS for, when a message was
+received with the REQUIRETLS option: the next-hop server must offer
+a matching TLS server certificate, and the server must announce
+REQUIRETLS support). Such a message will be returned to the sender
+if some REQUIRETLS requirement cannot be satisfied. These "hard"
+REQUIRETLS failures are logged as "REQUIRETLS failure". </p>
+
+<p> Other messages that were received with the REQUIRETLS option
+will be delivered with REQUIRETLS if possible. If not, a message
+will be delivered as if it was received without the REQUIRETLS
+option. This allows a mail sending site to discover when REQUIRETLS
+can be enforced, without disrupting email deliveries. These "soft"
+REQUIRETLS failures are logged with "REQUIRETLS Debug". </p>
+
+<p> On a perimeter MTA, it can make sense to turn off REQUIRETLS
+enforcement, or even to turn off REQUIRETLS support, when delivering
+a message to an internal destination. The internal servers may not
+support REQUIRETLS, and their connections may be secured with means
+other than DANE, STS, and the like. </p>
+
+<p> The supported syntax differs with SMTP and LMTP: </p>
+
+<ul> 
+
+<li> <p> With SMTP, specify a list of next-hop domain names (without
+the ":port" or ":service" suffix), "/file/name" patterns or
+"type:table" lookup tables, separated by commas and/or whitespace.
+Continue long lines by starting the next line with whitespace. A
+"/file/name" pattern is replaced by its contents.  A "type:table"
+lookup table is matched when a domain appears as lookup key. Specify
+"!pattern" to exclude a domain. </p>
+
+<li> <p> With LMTP, specify list of domain names (without the "inet":
+prefix, or  ":port" or ":service" suffix), or UNIX-domain socket
+"/path/name" (without the "unix:" prefix), or "type:table" lookup
+tables, separated by commas and/or whitespace. Continue long lines
+by starting the next line with whitespace. A "type:table" lookup
+table is matched when a domain appears as lookup key. Specify
+"!pattern" to exclude a domain or socket path. </p> 
+
+</ul>
+
+<p> Specify the form ".domain" to match any name ending in ".domain".
+To change this behavior, list "smtp_enforce_requiretls" or
+"lmtp_enforce_requiretls" in the parent_domain_matches_subdomains
+parameter value.  </p>
+
+<p>
+SMTP Examples:
+</p>
+
+<pre>
+# Enforce REQUIRETLS for SMTP with selected next-hop domains.
+smtp_enforce_requiretls = example.com, foo.example
+<br>
+# Enforce REQUIRETLS for SMTP with all but a few next-hop domains.
+smtp_enforce_requiretls = !foo.example, static:all
+</pre>
+
+<p>
+LMTP examples:
+</p>
+
+<pre>
+# Don't enforce REQUIRETLS 
+lmtp_enforce_requiretls =
+<br>
+# Enforce REQUIRETLS for specific destinations.
+lmtp_enforce_requiretls = /path/to/socket, message-store.example
+</pre>
+
+<p> This feature is available in Postfix &ge; 3.11. </p>
+
+%PARAM lmtp_enforce_requiretls empty
+
+<p> The LMTP-specific version of the smtp_enforce_requiretls
+configuration parameter. See there for details. </p>
+
+<p> This feature is available in Postfix &ge; 3.11. </p>
+
 %PARAM smtpd_hide_client_session no
 
 <p> Do not include SMTP client session information in the Postfix

postfix/proto/stop

@@ -1664,6 +1664,9 @@ REQUIRETLS
 RequireTLS
 requiretls
 sendopts
+TODO
+Onoop
+Orequiretls
 tz
 GID
 SIGKILL

postfix/proto/stop.double-history

@@ -159,10 +159,17 @@ proto  proto socketmap_table
  qmgr qmgr_deliver c qmgr qmgr_message c qmqpd qmqpd c 
  smtp smtp_proto c smtpd smtpd c verify verify c 
  operations Files cleanup cleanup h cleanup cleanup_message c 
- proto postconf proto pipe pipe c 
+ global ehlo_mask_test c local forward c smtpd smtpd c 
+ more alternate MX servers to try Files smtp smtp h 
+ Files sendmail sendmail c global rec_types h 
+ Files sendmail sendmail c 
+ Files sendmail sendmail c global rec_types h pickup pickup c 
+ pipe pipe c sendmail sendmail c 
+ smtp smtp c smtp smtp_proto c 
  bounce bounce c bounce bounce_notify_util c cleanup cleanup c 
  cleanup cleanup_message c smtp smtp c smtp smtp_connect c 
  Documentation edited for clarity Files pipe pipe c 
+ servers to try Files smtp smtp h smtp smtp_proto c 
  global mail_params h smtpd smtpd c 
  global mail_params h proto postconf proto smtp smtp c 
  proto postconf proto proto TLS_README html 

postfix/proto/stop.spell-cc

@@ -1858,6 +1858,7 @@ TINYCDB
 getdata
 XXXSENDOPTS
 xtra
+NODICT
 HAPROXY
 SRVR
 DGST

postfix/proto/stop.spell-history

@@ -100,6 +100,7 @@ Roessner
 bitflags
 Schulze
 tlspol
+TlsRequired
 Gueven
 Oemer
 Kozmenko

postfix/src/bounce/bounce_notify_service.c

@@ -98,6 +98,15 @@ int     bounce_notify_service(int flags, char *service, char *queue_name,
     char   *postmaster;
     int     count;
 
+    /*
+     * If the original sender requested REQUIRETLS, return headers only, and
+     * do not enforce REQUIRETLS for the delivery status notification.
+     */
+    if ((sendopts & SOPT_REQUIRETLS_ESMTP) != 0) {
+	dsn_ret = DSN_RET_HDRS;
+	sendopts &= ~SOPT_REQUIRETLS_ESMTP;
+    }
+
     /*
      * Initialize. Open queue file, bounce log, etc.
      * 
@@ -196,7 +205,8 @@ int     bounce_notify_service(int flags, char *service, char *queue_name,
 		    && bounce_header_dsn(bounce, bounce_info) == 0
 		    && bounce_diagnostic_dsn(bounce, bounce_info,
 					     DSN_NOTIFY_OVERRIDE) > 0) {
-		    bounce_original(bounce, bounce_info, DSN_RET_FULL);
+		    bounce_original(bounce, bounce_info, dsn_ret ?
+				    dsn_ret : DSN_RET_FULL);
 		    bounce_status = post_mail_fclose(bounce);
 		    if (bounce_status == 0)
 			msg_info("%s: postmaster non-delivery notification: %s",

postfix/src/bounce/bounce_notify_util.c

@@ -537,6 +537,7 @@ int     bounce_header(VSTREAM *bounce, BOUNCE_INFO *bounce_info,
      * Trade confidentiality against availability.
      */
     if (var_tls_required_enable
+	&& (bounce_info->sendopts & SOPT_REQUIRETLS_ESMTP) == 0
 	&& (bounce_info->sendopts & SOPT_REQUIRETLS_HEADER) != 0)
 	post_mail_fprintf(bounce, "TLS-Required: no");
 

postfix/src/bounce/bounce_notify_verp.c

@@ -111,6 +111,15 @@ int     bounce_notify_verp(int flags, char *service, char *queue_name,
     if (strcasecmp_utf8(recipient, mail_addr_double_bounce()) == 0)
 	msg_panic("%s: attempt to bounce a double bounce", myname);
 
+    /*
+     * If the original sender requested REQUIRETLS, return headers only, and
+     * do not enforce REQUIRETLS for the delivery status notification.
+     */
+    if ((sendopts & SOPT_REQUIRETLS_ESMTP) != 0) {
+	dsn_ret = DSN_RET_HDRS;
+	sendopts &= ~SOPT_REQUIRETLS_ESMTP;
+    }
+
     /*
      * Initialize. Open queue file, bounce log, etc.
      */

postfix/src/bounce/bounce_one_service.c

@@ -96,6 +96,15 @@ int     bounce_one_service(int flags, char *queue_name, char *queue_id,
 				    var_notify_classes);
     VSTRING *new_id = vstring_alloc(10);
 
+    /*
+     * If the original sender requested REQUIRETLS, return headers only, and
+     * do not enforce REQUIRETLS for the delivery status notification.
+     */
+    if ((sendopts & SOPT_REQUIRETLS_ESMTP) != 0) {
+	dsn_ret = DSN_RET_HDRS;
+	sendopts &= ~SOPT_REQUIRETLS_ESMTP;
+    }
+
     /*
      * Initialize. Open queue file, bounce log, etc.
      */
@@ -162,7 +171,8 @@ int     bounce_one_service(int flags, char *queue_name, char *queue_id,
 		    && bounce_recipient_log(bounce, bounce_info) == 0
 		    && bounce_header_dsn(bounce, bounce_info) == 0
 		    && bounce_recipient_dsn(bounce, bounce_info) == 0)
-		    bounce_original(bounce, bounce_info, DSN_RET_FULL);
+		    bounce_original(bounce, bounce_info, dsn_ret ?
+				    dsn_ret : DSN_RET_FULL);
 		bounce_status = post_mail_fclose(bounce);
 		if (bounce_status == 0)
 		    msg_info("%s: postmaster non-delivery notification: %s",

postfix/src/bounce/bounce_trace_service.c

@@ -95,6 +95,15 @@ int     bounce_trace_service(int flags, char *service, char *queue_name,
     int     count;
     const char *sender;
 
+    /*
+     * If the original sender requested REQUIRETLS, do not enforce REQUIRETLS
+     * for the delivery status notification. The trace service always returns
+     * headers only.
+     */
+    if ((sendopts & SOPT_REQUIRETLS_ESMTP) != 0) {
+	sendopts &= ~SOPT_REQUIRETLS_ESMTP;
+    }
+
     /*
      * For consistency with fail/delay notifications, send notification for a
      * non-bounce message as a single-bounce message, send notification for a

postfix/src/bounce/bounce_warn_service.c

@@ -98,6 +98,15 @@ int     bounce_warn_service(int unused_flags, char *service, char *queue_name,
     char   *postmaster;
     int     count;
 
+    /*
+     * If the original sender requested REQUIRETLS, return headers only, and
+     * do not enforce REQUIRETLS for the delivery status notification.
+     */
+    if ((sendopts & SOPT_REQUIRETLS_ESMTP) != 0) {
+	dsn_ret = DSN_RET_HDRS;
+	sendopts &= ~SOPT_REQUIRETLS_ESMTP;
+    }
+
     /*
      * Initialize. Open queue file, bounce log, etc.
      * 
@@ -185,7 +194,8 @@ int     bounce_warn_service(int unused_flags, char *service, char *queue_name,
 		    && bounce_header_dsn(bounce, bounce_info) == 0
 		    && bounce_diagnostic_dsn(bounce, bounce_info,
 					     DSN_NOTIFY_OVERRIDE) > 0) {
-		    bounce_original(bounce, bounce_info, DSN_RET_FULL);
+		    bounce_original(bounce, bounce_info, dsn_ret ?
+				    dsn_ret : DSN_RET_FULL);
 		    bounce_status = post_mail_fclose(bounce);
 		    if (bounce_status == 0)
 			msg_info("%s: postmaster delay notification: %s",

postfix/src/cleanup/cleanup_api.c

@@ -80,6 +80,8 @@
 /* .IP CLEANUP_FLAG_AUTOUTF8
 /*	Autodetection: request SMTPUTF8 support if the message
 /*	contains an UTF8 message header, sender, or recipient.
+/* .IP CLEANUP_FLAG_REQUIRETLS
+/*	The sender requested REQUIRETLS (RFC 8689) enforcement.
 /* DIAGNOSTICS
 /*	Problems and transactions are logged to \fBsyslogd\fR(8)
 /*	or \fBpostlogd\fR(8).
@@ -208,9 +210,15 @@ void    cleanup_control(CLEANUP_STATE *state, int flags)
     } else {
 	state->err_mask = ~0;
     }
+
+    /*
+     * Propagate requests that are specified at the envelope level. This may
+     * be augmented later with information derived from message content.
+     */
     if (state->flags & CLEANUP_FLAG_SMTPUTF8)
 	state->sendopts |= SMTPUTF8_FLAG_REQUESTED;
-    /* TODO(wietse) REQUIRETLS. */
+    if (state->flags & CLEANUP_FLAG_REQUIRETLS)
+	state->sendopts |= SOPT_REQUIRETLS_ESMTP;
     if (msg_verbose)
 	msg_info("server flags = %s", cleanup_strflags(state->flags));
 }

postfix/src/global/Makefile.in

@@ -124,7 +124,7 @@ TESTPROG= domain_list dot_lockfile mail_addr_crunch mail_addr_find \
 	off_cvt quote_822_local rec2stream recdump resolve_clnt \
 	resolve_local rewrite_clnt stream2rec string_list tok822_parse \
 	quote_821_local mail_conf_time mime_state strip_addr \
-	verify_clnt xtext anvil_clnt scache ehlo_mask \
+	verify_clnt xtext anvil_clnt scache ehlo_mask_test \
 	valid_mailhost_addr own_inet_addr header_body_checks \
 	data_redirect addr_match_list safe_ultostr verify_sender_addr \
 	mail_version mail_dict server_acl uxtext mail_parm_split \
@@ -336,7 +336,7 @@ anvil_clnt: $(LIB) $(LIBS)
 scache: scache.c $(LIB) $(LIBS)
 	$(CC) $(CFLAGS) -DTEST -o $@ $@.c $(LIB) $(LIBS) $(SYSLIBS)
 
-ehlo_mask: ehlo_mask.c $(LIB) $(LIBS)
+ehlo_mask_test: ehlo_mask_test.c $(LIB) $(LIBS)
 	$(CC) $(CFLAGS) -DTEST -o $@ $@.c $(LIB) $(LIBS) $(SYSLIBS)
 
 valid_mailhost_addr: valid_mailhost_addr.c $(LIB) $(LIBS)
@@ -416,7 +416,7 @@ config_known_tcp_ports: config_known_tcp_ports.c $(LIB) $(LIBS)
 	$(CC) $(CFLAGS) -DTEST -o $@ $@.c $(LIB) $(LIBS) $(SYSLIBS)
 
 tests: tok822_test mime_tests strip_addr_test tok822_limit_test \
-	xtext_test scache_multi_test ehlo_mask_test \
+	xtext_test scache_multi_test test_ehlo_mask \
 	namadr_list_test mail_conf_time_test header_body_checks_tests \
 	mail_version_test server_acl_test resolve_local_test maps_test \
 	safe_ultostr_test mail_parm_split_test fold_addr_test \
@@ -616,10 +616,8 @@ scache_multi_test: scache scache_multi.in scache_multi.ref
 	diff scache_multi.ref scache_multi.tmp
 	rm -f scache_multi.tmp
 
-ehlo_mask_test: ehlo_mask ehlo_mask.in ehlo_mask.ref
+test_ehlo_mask: ehlo_mask_test
-	$(SHLIB_ENV) $(VALGRIND) ./ehlo_mask <ehlo_mask.in >ehlo_mask.tmp
+	$(SHLIB_ENV) $(VALGRIND) ./ehlo_mask_test
-	diff ehlo_mask.ref ehlo_mask.tmp
-	rm -f ehlo_mask.tmp
 
 namadr_list_test: namadr_list namadr_list.in namadr_list.ref
 	-$(SHLIB_ENV) sh namadr_list.in >namadr_list.tmp 2>&1
@@ -1481,6 +1479,16 @@ ehlo_mask.o: ../../include/vbuf.h
 ehlo_mask.o: ../../include/vstring.h
 ehlo_mask.o: ehlo_mask.c
 ehlo_mask.o: ehlo_mask.h
+ehlo_mask_test.o: ../../include/check_arg.h
+ehlo_mask_test.o: ../../include/msg.h
+ehlo_mask_test.o: ../../include/msg_vstream.h
+ehlo_mask_test.o: ../../include/stringops.h
+ehlo_mask_test.o: ../../include/sys_defs.h
+ehlo_mask_test.o: ../../include/vbuf.h
+ehlo_mask_test.o: ../../include/vstream.h
+ehlo_mask_test.o: ../../include/vstring.h
+ehlo_mask_test.o: ehlo_mask.h
+ehlo_mask_test.o: ehlo_mask_test.c
 ext_prop.o: ../../include/check_arg.h
 ext_prop.o: ../../include/name_mask.h
 ext_prop.o: ../../include/sys_defs.h

postfix/src/global/addr_match_list.c

@@ -42,6 +42,10 @@
 /*	Request that addr_match_list_match() logs a warning and
 /*	returns zero with list->error set to a non-zero dictionary
 /*	error code, instead of raising a fatal error.
+/* .IP MATCH_FLAG_NOFILE
+/*	Disable special handling for /file/name.
+/* .IP MATCH_FLAG_NODICT
+/*	Disable special handling for type:name.
 /* .PP
 /*	Specify MATCH_FLAG_NONE to request none of the above.
 /*	The last argument is a list of patterns, or the absolute
@@ -67,6 +71,9 @@
 /*	IBM T.J. Watson Research
 /*	P.O. Box 704
 /*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	porcupine.org
 /*--*/
 
 /* System library. */

postfix/src/global/cleanup_strflags.c

@@ -55,6 +55,7 @@ static struct cleanup_flag_map cleanup_flag_map[] = {
     CLEANUP_FLAG_SMTP_REPLY, "enable_smtp_reply",
     CLEANUP_FLAG_SMTPUTF8, "smtputf8_requested",
     CLEANUP_FLAG_AUTOUTF8, "smtputf8_autodetect",
+    CLEANUP_FLAG_REQUIRETLS, "requiretls_requested",
 };
 
 /* cleanup_strflags - map flags code to printable string */

postfix/src/global/cleanup_user.h

@@ -25,6 +25,7 @@
 #define CLEANUP_FLAG_SMTP_REPLY	(1<<7)	/* Enable SMTP reply */
 #define CLEANUP_FLAG_SMTPUTF8	(1<<8)	/* SMTPUTF8 requested */
 #define CLEANUP_FLAG_AUTOUTF8	(1<<9)	/* Autodetect SMTPUTF8 */
+#define CLEANUP_FLAG_REQUIRETLS	(1<<10)	/* REQUIRETLS requested */
 
 #define CLEANUP_FLAG_FILTER_ALL	(CLEANUP_FLAG_FILTER | CLEANUP_FLAG_MILTER)
 

postfix/src/global/domain_list.c

@@ -45,6 +45,10 @@
 /*	Request that domain_list_match() logs a warning and returns
 /*	zero, with list->error set to a non-zero dictionary error
 /*	code, instead of raising a fatal error.
+/* .IP MATCH_FLAG_NOFILE
+/*	Disable special handling for /file/name.
+/* .IP MATCH_FLAG_NODICT
+/*	Disable special handling for type:name.
 /* .PP
 /*	Specify MATCH_FLAG_NONE to request none of the above.
 /*	The last argument is a list of domain patterns, or the name of
@@ -69,6 +73,9 @@
 /*	IBM T.J. Watson Research
 /*	P.O. Box 704
 /*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	porcupine.org
 /*--*/
 
 /* System library. */

postfix/src/global/ehlo_mask.c

@@ -20,6 +20,7 @@
 /*	#define EHLO_MASK_DSN		(1<<11)
 /*	#define EHLO_MASK_SMTPUTF8	(1<<12)
 /*	#define EHLO_MASK_CHUNKING	(1<<13)
+/*	#define EHLO_MASK_REQUIRETLS	(1<<14)
 /*	#define EHLO_MASK_SILENT	(1<<15)
 /*
 /*	int	ehlo_mask(keyword_list)
@@ -70,22 +71,22 @@
   * The lookup table.
   */
 static const NAME_MASK ehlo_mask_table[] = {
-    "8BITMIME", EHLO_MASK_8BITMIME,
+    EHLO_VERB_8BITMIME, EHLO_MASK_8BITMIME,
-    "AUTH", EHLO_MASK_AUTH,
+    EHLO_VERB_AUTH, EHLO_MASK_AUTH,
-    "ETRN", EHLO_MASK_ETRN,
+    EHLO_VERB_ETRN, EHLO_MASK_ETRN,
-    "PIPELINING", EHLO_MASK_PIPELINING,
+    EHLO_VERB_PIPELINING, EHLO_MASK_PIPELINING,
-    "SIZE", EHLO_MASK_SIZE,
+    EHLO_VERB_SIZE, EHLO_MASK_SIZE,
-    "VERP", EHLO_MASK_VERP,
+    EHLO_VERB_VERP, EHLO_MASK_VERP,
-    "VRFY", EHLO_MASK_VRFY,
+    EHLO_VERB_VRFY, EHLO_MASK_VRFY,
-    "XCLIENT", EHLO_MASK_XCLIENT,
+    EHLO_VERB_XCLIENT, EHLO_MASK_XCLIENT,
-    "XFORWARD", EHLO_MASK_XFORWARD,
+    EHLO_VERB_XFORWARD, EHLO_MASK_XFORWARD,
-    "STARTTLS", EHLO_MASK_STARTTLS,
+    EHLO_VERB_STARTTLS, EHLO_MASK_STARTTLS,
-    "ENHANCEDSTATUSCODES", EHLO_MASK_ENHANCEDSTATUSCODES,
+    EHLO_VERB_ENHANCEDSTATUSCODES, EHLO_MASK_ENHANCEDSTATUSCODES,
-    "DSN", EHLO_MASK_DSN,
+    EHLO_VERB_DSN, EHLO_MASK_DSN,
-    "EHLO_MASK_SMTPUTF8", EHLO_MASK_SMTPUTF8,
+    EHLO_VERB_SMTPUTF8, EHLO_MASK_SMTPUTF8,
-    "SMTPUTF8", EHLO_MASK_SMTPUTF8,
+    EHLO_VERB_CHUNKING, EHLO_MASK_CHUNKING,
-    "CHUNKING", EHLO_MASK_CHUNKING,
+    EHLO_VERB_REQUIRETLS, EHLO_MASK_REQUIRETLS,
-    "SILENT-DISCARD", EHLO_MASK_SILENT,	/* XXX In-band signaling */
+    EHLO_VERB_SILENT, EHLO_MASK_SILENT,
     0,
 };
 
@@ -114,32 +115,3 @@ const char *str_ehlo_mask(int mask_bits)
      */
     return (str_name_mask("ehlo bitmask", ehlo_mask_table, mask_bits));
 }
-
-#ifdef TEST
-
- /*
-  * Stand-alone test program.
-  */
-#include <stdlib.h>
-#include <vstream.h>
-#include <vstring.h>
-#include <vstring_vstream.h>
-
-int     main(int unused_argc, char **unused_argv)
-{
-    int     mask_bits;
-    VSTRING *buf = vstring_alloc(1);
-    const char *mask_string;
-
-    while (vstring_get_nonl(buf, VSTREAM_IN) != VSTREAM_EOF) {
-	mask_bits = ehlo_mask(vstring_str(buf));
-	mask_string = str_ehlo_mask(mask_bits);
-	vstream_printf("%s -> 0x%x -> %s\n", vstring_str(buf), mask_bits,
-		       mask_string);
-	vstream_fflush(VSTREAM_OUT);
-    }
-    vstring_free(buf);
-    exit(0);
-}
-
-#endif

postfix/src/global/ehlo_mask.h

@@ -12,7 +12,7 @@
 /* .nf
 
  /*
-  * External interface.
+  * Bit flags.
   */
 #define EHLO_MASK_8BITMIME	(1<<0)	/* start of first byte */
 #define EHLO_MASK_PIPELINING	(1<<1)
@@ -29,8 +29,32 @@
 #define EHLO_MASK_DSN		(1<<11)
 #define EHLO_MASK_SMTPUTF8	(1<<12)
 #define EHLO_MASK_CHUNKING	(1<<13)
-#define EHLO_MASK_SILENT	(1<<15)
+#define EHLO_MASK_REQUIRETLS	(1<<14)
+#define EHLO_MASK_SILENT	(1<<15)	/* in-band signaling */
 
+ /*
+  * ESMTP verbs.
+  */
+#define EHLO_VERB_8BITMIME 	"8BITMIME"
+#define EHLO_VERB_PIPELINING 	"PIPELINING"
+#define EHLO_VERB_SIZE 		"SIZE"
+#define EHLO_VERB_VRFY 		"VRFY"
+#define EHLO_VERB_ETRN 		"ETRN"
+#define EHLO_VERB_AUTH 		"AUTH"
+#define EHLO_VERB_VERP 		"VERP"
+#define EHLO_VERB_STARTTLS 	"STARTTLS"
+#define EHLO_VERB_XCLIENT 	"XCLIENT"
+#define EHLO_VERB_XFORWARD 	"XFORWARD"
+#define EHLO_VERB_ENHANCEDSTATUSCODES 	"ENHANCEDSTATUSCODES"
+#define EHLO_VERB_DSN 		"DSN"
+#define EHLO_VERB_SMTPUTF8 	"SMTPUTF8"
+#define EHLO_VERB_CHUNKING 	"CHUNKING"
+#define EHLO_VERB_REQUIRETLS 	"REQUIRETLS"
+#define EHLO_VERB_SILENT 	"SILENT-DISCARD"	/* in-band signaling */
+
+ /*
+  * Functions.
+  */
 extern int ehlo_mask(const char *);
 extern const char *str_ehlo_mask(int);
 

postfix/src/global/ehlo_mask.in

@@ -1,3 +0,0 @@
-starttls, 8bitmime, verp, etrn, etrn
-foobar, auth, pipelining, size, vrfy
-xclient, xforward

postfix/src/global/ehlo_mask.ref

@@ -1,3 +0,0 @@
-starttls, 8bitmime, verp, etrn, etrn -> 0xd1 -> 8BITMIME ETRN VERP STARTTLS
-foobar, auth, pipelining, size, vrfy -> 0x2e -> AUTH PIPELINING SIZE VRFY
-xclient, xforward -> 0x300 -> XCLIENT XFORWARD

postfix/src/global/ehlo_mask_test.c

@@ -0,0 +1,121 @@
+ /*
+  * System library.
+  */
+#include <sys_defs.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stringops.h>
+
+ /*
+  * Utility library.
+  */
+#include <msg.h>
+#include <msg_vstream.h>
+#include <vstream.h>
+#include <vstring.h>
+
+ /*
+  * Global library.
+  */
+#include <ehlo_mask.h>
+
+ /*
+  * Tests and test cases.
+  */
+typedef struct TEST_CASE {
+    const char *label;			/* identifies test case */
+    int     mask;
+    const char *want;
+} TEST_CASE;
+
+ /*
+  * Verify that each verb has its unique bit mask.
+  */
+static const TEST_CASE test_cases[] = {
+    {"EHLO_MASK_8BITMIME",
+	EHLO_MASK_8BITMIME,
+	"8BITMIME"
+    },
+    {"EHLO_MASK_PIPELINING",
+	EHLO_MASK_PIPELINING,
+	"PIPELINING"
+    },
+    {"EHLO_MASK_SIZE",
+	EHLO_MASK_SIZE,
+	"SIZE"
+    },
+    {"EHLO_MASK_VRFY",
+	EHLO_MASK_VRFY,
+	"VRFY"
+    },
+    {"EHLO_MASK_ETRN",
+	EHLO_MASK_ETRN,
+	"ETRN"
+    },
+    {"EHLO_MASK_AUTH",
+	EHLO_MASK_AUTH,
+	"AUTH"
+    },
+    {"EHLO_MASK_VERP",
+	EHLO_MASK_VERP,
+	"VERP"
+    },
+    {"EHLO_MASK_STARTTLS",
+	EHLO_MASK_STARTTLS,
+	"STARTTLS"
+    },
+    {"EHLO_MASK_XCLIENT",
+	EHLO_MASK_XCLIENT,
+	"XCLIENT"
+    },
+    {"EHLO_MASK_ENHANCEDSTATUSCODES",
+	EHLO_MASK_ENHANCEDSTATUSCODES,
+	"ENHANCEDSTATUSCODES"
+    },
+    {"EHLO_MASK_DSN",
+	EHLO_MASK_DSN,
+	"DSN"
+    },
+    {"EHLO_MASK_SMTPUTF8",
+	EHLO_MASK_SMTPUTF8,
+	"SMTPUTF8"
+    },
+    {"EHLO_MASK_CHUNKING",
+	EHLO_MASK_CHUNKING,
+	"CHUNKING"
+    },
+    {"EHLO_MASK_REQUIRETLS",
+	EHLO_MASK_REQUIRETLS,
+	"REQUIRETLS"
+    },
+    {"EHLO_MASK_SILENT",
+	EHLO_MASK_SILENT,
+	"SILENT-DISCARD"
+    },
+    {0},
+};
+
+int     main(int argc, char **argv)
+{
+    const TEST_CASE *tp;
+    int     pass = 0;
+    int     fail = 0;
+    const char *got;
+
+    msg_vstream_init(sane_basename((VSTRING *) 0, argv[0]), VSTREAM_ERR);
+
+    for (tp = test_cases; tp->label != 0; tp++) {
+	msg_info("RUN  %s", tp->label);
+	got = str_ehlo_mask(tp->mask);
+	if (strcmp(got, tp->want) != 0) {
+	    msg_warn("got result '%s', want: '%s'", got, tp->want);
+	    fail++;
+	    msg_info("FAIL %s", tp->label);
+	} else {
+	    msg_info("PASS %s", tp->label);
+	    pass++;
+	}
+    }
+    msg_info("PASS=%d FAIL=%d", pass, fail);
+    exit(fail != 0);
+}

postfix/src/global/mail_params.c

@@ -128,6 +128,7 @@
 /*	int	var_smtputf8_enable;
 /*	int	var_strict_smtputf8;
 /*	char	*var_smtputf8_autoclass;
+/*	int	var_requiretls_enable;
 /*	int	var_tls_required_enable;
 /*	int     var_idna2003_compat;
 /*	char	*var_compatibility_level;
@@ -370,6 +371,7 @@ char   *var_dsn_filter;
 int     var_smtputf8_enable;
 int     var_strict_smtputf8;
 char   *var_smtputf8_autoclass;
+int     var_requiretls_enable;
 int     var_tls_required_enable;
 int     var_idna2003_compat;
 char   *var_compatibility_level;
@@ -793,6 +795,7 @@ void    mail_params_init()
 	VAR_SMTPUTF8_ENABLE, DEF_SMTPUTF8_ENABLE, &var_smtputf8_enable,
 	VAR_IDNA2003_COMPAT, DEF_IDNA2003_COMPAT, &var_idna2003_compat,
 	VAR_RESPECTFUL_LOGGING, DEF_RESPECTFUL_LOGGING, &var_respectful_logging,
+	VAR_REQUIRETLS_ENABLE, DEF_REQUIRETLS_ENABLE, &var_requiretls_enable,
 	VAR_TLSREQUIRED_ENABLE, DEF_TLSREQUIRED_ENABLE, &var_tls_required_enable,
 	0,
     };

postfix/src/global/mail_params.h

@@ -4403,6 +4403,17 @@ extern int var_idna2003_compat;
 #define DEF_TLSREQUIRED_ENABLE		"yes"
 extern int var_tls_required_enable;
 
+#define VAR_REQUIRETLS_ENABLE		"requiretls_enable"
+#define DEF_REQUIRETLS_ENABLE		"yes"
+extern int var_requiretls_enable;
+
+#define VAR_SMTP_ENFORCE_REQUIRETLS	"smtp_enforce_requiretls"
+#define DEF_SMTP_ENFORCE_REQUIRETLS	""
+extern char *var_smtp_enforce_requiretls;
+
+#define VAR_LMTP_ENFORCE_REQUIRETLS	"lmtp_enforce_requiretls"
+#define DEF_LMTP_ENFORCE_REQUIRETLS	""
+
  /*
   * Workaround for future incompatibility. Our implementation of RFC 2308
   * negative reply caching relies on the promise that res_query() and

postfix/src/global/namadr_list.c

@@ -51,6 +51,10 @@
 /*	Request that namadr_list_match() logs a warning and returns
 /*	zero with list->error set to a non-zero dictionary error
 /*	code, instead of raising a fatal error.
+/* .IP MATCH_FLAG_NOFILE
+/*	Disable special handling for /file/name.
+/* .IP MATCH_FLAG_NODICT
+/*	Disable special handling for type:name.
 /* .PP
 /*	Specify MATCH_FLAG_NONE to request none of the above.
 /*	The last argument is a list of patterns, or the absolute
@@ -75,6 +79,9 @@
 /*	IBM T.J. Watson Research
 /*	P.O. Box 704
 /*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	porcupine.org
 /*--*/
 
 /* System library. */

postfix/src/global/post_mail.c

@@ -225,8 +225,8 @@ static void post_mail_init(VSTREAM *stream, const char *sender,
     int     cleanup_flags =
     int_filt_flags(source_class) | CLEANUP_FLAG_MASK_INTERNAL
     | smtputf8_autodetect(source_class)
+    | ((sendopts & SOPT_REQUIRETLS_ESMTP) ? CLEANUP_FLAG_REQUIRETLS : 0)
     | ((sendopts & SMTPUTF8_FLAG_REQUESTED) ? CLEANUP_FLAG_SMTPUTF8 : 0);
-    /* TODO(wietse) REQUIRETLS. */
 
     GETTIMEOFDAY(&now);
     date = mail_date(now.tv_sec);

postfix/src/global/rec_type.h

@@ -110,7 +110,7 @@
  /*
   * The subset of inputs that the postdrop command allows.
   */
-#define REC_TYPE_POST_ENVELOPE	"MFSRVAin"
+#define REC_TYPE_POST_ENVELOPE	"MCFSRVAin"
 #define REC_TYPE_POST_CONTENT	"XLN"
 #define REC_TYPE_POST_EXTRACT	"EAR"
 

postfix/src/global/string_list.c

@@ -39,6 +39,10 @@
 /*	Request that string_list_match() logs a warning and returns
 /*	zero with list->error set to a non-zero dictionary error
 /*	code, instead of raising a fatal error.
+/* .IP MATCH_FLAG_NOFILE
+/*	Disable special handling for /file/name.
+/* .IP MATCH_FLAG_NODICT
+/*	Disable special handling for type:name.
 /* .PP
 /*	Specify MATCH_FLAG_NONE to request none of the above.
 /*	The last argument specifies a list of string patterns.
@@ -61,6 +65,9 @@
 /*	IBM T.J. Watson Research
 /*	P.O. Box 704
 /*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	porcupine.org
 /*--*/
 
 /* System library. */

postfix/src/local/forward.c

@@ -163,9 +163,10 @@ static FORWARD_INFO *forward_open(DELIVER_REQUEST *request, const char *sender)
 #define FORWARD_CLEANUP_FLAGS \
 	(CLEANUP_FLAG_BOUNCE | CLEANUP_FLAG_MASK_INTERNAL \
 	| smtputf8_autodetect(MAIL_SRC_MASK_FORWARD) \
+	| ((request->sendopts & SOPT_REQUIRETLS_ESMTP) ? \
+	CLEANUP_FLAG_REQUIRETLS : 0) \
 	| ((request->sendopts & SMTPUTF8_FLAG_REQUESTED) ? \
 	CLEANUP_FLAG_SMTPUTF8 : 0))
-	/* TODO(wietse) REQUIRETLS. */
 
     attr_print(cleanup, ATTR_FLAG_NONE,
 	       SEND_ATTR_INT(MAIL_ATTR_FLAGS, FORWARD_CLEANUP_FLAGS),

postfix/src/pickup/pickup.c

@@ -236,6 +236,7 @@ static int copy_segment(VSTREAM *qfile, VSTREAM *cleanup, PICKUP_INFO *info,
     char   *attr_value;
     char   *saved_attr;
     int     skip_attr;
+    ssize_t count;
 
     /*
      * Limit the input record size. All front-end programs should protect the
@@ -246,7 +247,7 @@ static int copy_segment(VSTREAM *qfile, VSTREAM *cleanup, PICKUP_INFO *info,
      * 
      * We must allow PTR records here because of "postsuper -r".
      */
-    for (;;) {
+    for (count = 0; /* void */; count++) {
 	if ((type = rec_get(qfile, buf, var_line_limit)) < 0
 	    || strchr(expected, type) == 0)
 	    return (file_read_error(info, type));
@@ -264,6 +265,9 @@ static int copy_segment(VSTREAM *qfile, VSTREAM *cleanup, PICKUP_INFO *info,
 	}
 	if (type == REC_TYPE_TIME)
 	    time_seen = 1;
+	if (type == REC_TYPE_SIZE && count > 5)
+	    /* Discard SIZE record not at beginning of segment. */
+	    continue;
 
 	/*
 	 * XXX Workaround: REC_TYPE_FILT (used in envelopes) == REC_TYPE_CONT

postfix/src/pipe/Makefile.in

@@ -83,6 +83,7 @@ pipe.o: ../../include/pipe_command.h
 pipe.o: ../../include/quote_822_local.h
 pipe.o: ../../include/quote_flags.h
 pipe.o: ../../include/recipient_list.h
+pipe.o: ../../include/sendopts.h
 pipe.o: ../../include/sent.h
 pipe.o: ../../include/set_eugid.h
 pipe.o: ../../include/split_addr.h

postfix/src/pipe/pipe.c

@@ -284,6 +284,14 @@
 /* .sp
 /*	This information is modified by the \fBhqu\fR flags for quoting
 /*	and case folding.
+/* .IP \fB${requiretls}\fR
+/*	This feature should be used with content filters that pass
+/*	filtered mail to the Postfix sendmail(1) command. The macro
+/*	expands to the sendmail(1) command-line option \fB-Orequiretls\fR
+/*	if the sender requested REQUIRETLS, otherwise it expands to
+/*	\fB-Onoop\fR.
+/* .sp
+/*	This feature is available as of Postfix 3.10.
 /* .IP \fB${sasl_method}\fR
 /*	This macro expands to the name of the SASL authentication
 /*	mechanism in the AUTH command when the Postfix SMTP server
@@ -519,6 +527,7 @@
 #include <delivered_hdr.h>
 #include <fold_addr.h>
 #include <mail_parm_split.h>
+#include <sendopts.h>
 
 /* Single server skeleton. */
 
@@ -553,6 +562,7 @@
 #define PIPE_DICT_SASL_SENDER	"sasl_sender"	/* key */
 #define PIPE_DICT_QUEUE_ID	"queue_id"	/* key */
 #define PIPE_DICT_ENVID		"envid"	/* key */
+#define PIPE_DICT_REQUIRETLS	"requiretls"	/* key */
 
  /*
   * Flags used to pass back the type of special parameter found by
@@ -659,6 +669,7 @@ static int parse_callback(int type, VSTRING *buf, void *context)
 	PIPE_DICT_SASL_SENDER, 0,
 	PIPE_DICT_QUEUE_ID, 0,
 	PIPE_DICT_ENVID, 0,
+	PIPE_DICT_REQUIRETLS, 0,
 	0, 0,
     };
     struct cmd_flags *p;
@@ -1290,6 +1301,9 @@ static int deliver_message(DELIVER_REQUEST *request, char *service, char **argv)
 		request->queue_id);
     dict_update(PIPE_DICT_TABLE, PIPE_DICT_ENVID,
 		request->dsn_envid);
+    dict_update(PIPE_DICT_TABLE, PIPE_DICT_REQUIRETLS,
+		(request->sendopts & SOPT_REQUIRETLS_ESMTP)
+		&& var_requiretls_enable ? "-Orequiretls" : "-Onoop");
     vstring_free(buf);
 
     if ((expanded_argv = expand_argv(service, attr.command,

postfix/src/postconf/Makefile.in

@@ -1065,15 +1065,6 @@ test76:	$(PROG) test76.ref
 	diff /dev/null test76.tmp
 	rm -f main.cf master.cf test76.tmp
 
-test77: $(PROG) test77-main.cf test77.ref
-	rm -f main.cf master.cf
-	cp test77-main.cf main.cf
-	touch master.cf
-	touch -t 197701010000 main.cf
-	$(HTABLE_FIX) $(SHLIB_ENV) $(VALGRIND) ./$(PROG) -nc . >test77.tmp 2>&1
-	diff test77.ref test77.tmp
-	rm -f main.cf master.cf test77.tmp
-
 # Warn about unused, deprecated, or deleted parameters.
 test78:	$(PROG) test78.ref
 	rm -f main.cf master.cf
@@ -1094,6 +1085,15 @@ test78:	$(PROG) test78.ref
 	diff /dev/null test78.tmp
 	rm -f main.cf master.cf test78.tmp
 
+test77: $(PROG) test77-main.cf test77.ref
+	rm -f main.cf master.cf
+	cp test77-main.cf main.cf
+	touch master.cf
+	touch -t 197701010000 main.cf
+	$(HTABLE_FIX) $(SHLIB_ENV) $(VALGRIND) ./$(PROG) -nc . >test77.tmp 2>&1
+	diff test77.ref test77.tmp
+	rm -f main.cf master.cf test77.tmp
+
 clean:
 	rm -f *.o *core $(PROG) $(TESTPROG) junk $(MAKES) $(AUTOS) $(DUMMIES) \
 	$(TEST_TMP) $(DB_MAKES)

postfix/src/sendmail/Makefile.in

@@ -86,6 +86,7 @@ sendmail.o: ../../include/recipient_list.h
 sendmail.o: ../../include/record.h
 sendmail.o: ../../include/resolve_clnt.h
 sendmail.o: ../../include/safe.h
+sendmail.o: ../../include/sendopts.h
 sendmail.o: ../../include/set_ugid.h
 sendmail.o: ../../include/split_at.h
 sendmail.o: ../../include/stringops.h

postfix/src/sendmail/sendmail.c

@@ -152,10 +152,28 @@
 /*	comma-separated list with one or more of \fBfailure\fR (send
 /*	notification when delivery fails), \fBdelay\fR (send
 /*	notification when delivery is delayed), or \fBsuccess\fR
-/*	(send notification when the message is delivered); or specify
+/*	(send notification after the message is delivered); or specify
 /*	\fBnever\fR (don't send any notifications at all).
 /*
 /*	This feature is available in Postfix 2.3 and later.
+/* .IP "\fB-O requiretls"
+/*	When delivering a message to an SMTP or LMTP server, the
+/*	connection must use TLS with a verified server certificate,
+/*	and the server must support REQUIRETLS. Try multiple servers if
+/*	possible, and return the message as undeliverable when these
+/*	requirements were not satisfied with any of the servers that
+/*	were tried. The "requiretls" option value is case-insensitive.
+/*
+/*	This feature is available in Postfix 3.10 and later.
+/* .IP "\fB-O smtputf8"
+/*	When delivering a message to an SMTP or LMTP server, the server
+/*	must support SMTPUTF8. Try multiple servers if possible, and
+/*	return the message as undeliverable when a message contains an
+/*	UTF8 envelope address or message header, but SMTPUTF8 was not
+/*	supported by any of the servers that were tried. The "smtputf8"
+/*	option value is case-insensitive.
+/*
+/*	This feature is available in Postfix 3.10 and later.
 /* .IP "\fB-n\fR (ignored)"
 /*	Backwards compatibility.
 /* .IP "\fB-oA\fIalias_database\fR"
@@ -434,6 +452,11 @@
 /*	the Postfix executable files and documentation with the default
 /*	Postfix instance, and that are started, stopped, etc., together
 /*	with the default Postfix instance.
+/* .PP
+/*	Postfix 3.10 and later:
+/* .IP "\fBrequiretls_enable (yes)\fR"
+/*	Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+/*	8689.
 /* FILES
 /*	/var/spool/postfix, mail queue
 /*	/etc/postfix, configuration files
@@ -537,6 +560,7 @@
 #include <user_acl.h>
 #include <dsn_mask.h>
 #include <mail_parm_split.h>
+#include <sendopts.h>
 
 /* Application-specific. */
 
@@ -589,6 +613,11 @@ static const CONFIG_STR_TABLE str_table[] = {
     0,
 };
 
+ /*
+  * Sender options.
+  */
+static int sm_sendopts;
+
  /*
   * Silly little macros (SLMs).
   */
@@ -788,6 +817,14 @@ static void enqueue(const int flags, const char *encoding,
      * With "sendmail -N", instead of a per-message NOTIFY record we store one
      * per recipient so that we can simplify the implementation somewhat.
      */
+    if (sm_sendopts)
+	rec_fprintf(dst, REC_TYPE_SIZE, REC_TYPE_SIZE_FORMAT,
+		    (REC_TYPE_SIZE_CAST1) ~ 0,	/* message segment size */
+		    (REC_TYPE_SIZE_CAST2) ~ 0,	/* content offset */
+		    (REC_TYPE_SIZE_CAST3) ~ 0,	/* recipient count */
+		    (REC_TYPE_SIZE_CAST4) ~ 0,	/* qmgr options */
+		    (REC_TYPE_SIZE_CAST5) ~ 0,	/* content length */
+		    (REC_TYPE_SIZE_CAST6) sm_sendopts);
     if (dsn_envid)
 	rec_fprintf(dst, REC_TYPE_ATTR, "%s=%s",
 		    MAIL_ATTR_DSN_ENVID, dsn_envid);
@@ -1251,7 +1288,20 @@ int     main(int argc, char **argv)
 	    break;
 	case 'N':
 	    if ((dsn_notify = dsn_notify_mask(optarg)) == 0)
-		msg_warn("bad -N option value -- ignored");
+		msg_warn("bad -N option value: '%s' -- ignored", optarg);
+	    break;
+	case 'O':
+	    /* NOOP is used to implement ${requiretls} in pipe(8). */
+	    if (strcasecmp(optarg, "REQUIRETLS") == 0) {
+		sm_sendopts |= SOPT_REQUIRETLS_ESMTP;
+	    if (var_requiretls_enable == 0)
+		msg_warn("'-O requiretls' was requested, but the "
+			 "configuration is 'requiretls_enable = no'");
+	    } else if (strcasecmp(optarg, "SMTPUTF8") == 0) {
+		sm_sendopts |= SOPT_SMTPUTF8_REQUESTED;
+	    } else if (strcasecmp(optarg, "NOOP") != 0) {
+		msg_warn("bad -O option value: '%s' -- ignored", optarg);
+	    }
 	    break;
 	case 'R':
 	    if ((dsn_ret = dsn_ret_code(optarg)) == 0)

postfix/src/smtp/Makefile.in

@@ -84,6 +84,7 @@ smtp.o: ../../include/deliver_request.h
 smtp.o: ../../include/delivered_hdr.h
 smtp.o: ../../include/dict.h
 smtp.o: ../../include/dns.h
+smtp.o: ../../include/domain_list.h
 smtp.o: ../../include/dsn.h
 smtp.o: ../../include/dsn_buf.h
 smtp.o: ../../include/ext_prop.h
@@ -134,6 +135,7 @@ smtp_addr.o: ../../include/check_arg.h
 smtp_addr.o: ../../include/deliver_request.h
 smtp_addr.o: ../../include/dict.h
 smtp_addr.o: ../../include/dns.h
+smtp_addr.o: ../../include/domain_list.h
 smtp_addr.o: ../../include/dsn.h
 smtp_addr.o: ../../include/dsn_buf.h
 smtp_addr.o: ../../include/header_body_checks.h
@@ -178,6 +180,7 @@ smtp_chat.o: ../../include/cleanup_user.h
 smtp_chat.o: ../../include/deliver_request.h
 smtp_chat.o: ../../include/dict.h
 smtp_chat.o: ../../include/dns.h
+smtp_chat.o: ../../include/domain_list.h
 smtp_chat.o: ../../include/dsn.h
 smtp_chat.o: ../../include/dsn_buf.h
 smtp_chat.o: ../../include/dsn_util.h
@@ -229,6 +232,7 @@ smtp_connect.o: ../../include/deliver_pass.h
 smtp_connect.o: ../../include/deliver_request.h
 smtp_connect.o: ../../include/dict.h
 smtp_connect.o: ../../include/dns.h
+smtp_connect.o: ../../include/domain_list.h
 smtp_connect.o: ../../include/dsn.h
 smtp_connect.o: ../../include/dsn_buf.h
 smtp_connect.o: ../../include/header_body_checks.h
@@ -284,6 +288,7 @@ smtp_key.o: ../../include/check_arg.h
 smtp_key.o: ../../include/deliver_request.h
 smtp_key.o: ../../include/dict.h
 smtp_key.o: ../../include/dns.h
+smtp_key.o: ../../include/domain_list.h
 smtp_key.o: ../../include/dsn.h
 smtp_key.o: ../../include/dsn_buf.h
 smtp_key.o: ../../include/header_body_checks.h
@@ -321,6 +326,7 @@ smtp_map11.o: ../../include/check_arg.h
 smtp_map11.o: ../../include/deliver_request.h
 smtp_map11.o: ../../include/dict.h
 smtp_map11.o: ../../include/dns.h
+smtp_map11.o: ../../include/domain_list.h
 smtp_map11.o: ../../include/dsn.h
 smtp_map11.o: ../../include/dsn_buf.h
 smtp_map11.o: ../../include/header_body_checks.h
@@ -361,6 +367,7 @@ smtp_misc.o: ../../include/check_arg.h
 smtp_misc.o: ../../include/deliver_request.h
 smtp_misc.o: ../../include/dict.h
 smtp_misc.o: ../../include/dns.h
+smtp_misc.o: ../../include/domain_list.h
 smtp_misc.o: ../../include/dsn.h
 smtp_misc.o: ../../include/dsn_buf.h
 smtp_misc.o: ../../include/ext_prop.h
@@ -404,6 +411,7 @@ smtp_proto.o: ../../include/defer.h
 smtp_proto.o: ../../include/deliver_request.h
 smtp_proto.o: ../../include/dict.h
 smtp_proto.o: ../../include/dns.h
+smtp_proto.o: ../../include/domain_list.h
 smtp_proto.o: ../../include/dsn.h
 smtp_proto.o: ../../include/dsn_buf.h
 smtp_proto.o: ../../include/dsn_mask.h
@@ -470,6 +478,7 @@ smtp_rcpt.o: ../../include/deliver_completed.h
 smtp_rcpt.o: ../../include/deliver_request.h
 smtp_rcpt.o: ../../include/dict.h
 smtp_rcpt.o: ../../include/dns.h
+smtp_rcpt.o: ../../include/domain_list.h
 smtp_rcpt.o: ../../include/dsn.h
 smtp_rcpt.o: ../../include/dsn_buf.h
 smtp_rcpt.o: ../../include/dsn_mask.h
@@ -510,6 +519,7 @@ smtp_reuse.o: ../../include/check_arg.h
 smtp_reuse.o: ../../include/deliver_request.h
 smtp_reuse.o: ../../include/dict.h
 smtp_reuse.o: ../../include/dns.h
+smtp_reuse.o: ../../include/domain_list.h
 smtp_reuse.o: ../../include/dsn.h
 smtp_reuse.o: ../../include/dsn_buf.h
 smtp_reuse.o: ../../include/header_body_checks.h
@@ -551,6 +561,7 @@ smtp_sasl_auth_cache.o: ../../include/deliver_request.h
 smtp_sasl_auth_cache.o: ../../include/dict.h
 smtp_sasl_auth_cache.o: ../../include/dict_proxy.h
 smtp_sasl_auth_cache.o: ../../include/dns.h
+smtp_sasl_auth_cache.o: ../../include/domain_list.h
 smtp_sasl_auth_cache.o: ../../include/dsn.h
 smtp_sasl_auth_cache.o: ../../include/dsn_buf.h
 smtp_sasl_auth_cache.o: ../../include/dsn_util.h
@@ -591,6 +602,7 @@ smtp_sasl_glue.o: ../../include/check_arg.h
 smtp_sasl_glue.o: ../../include/deliver_request.h
 smtp_sasl_glue.o: ../../include/dict.h
 smtp_sasl_glue.o: ../../include/dns.h
+smtp_sasl_glue.o: ../../include/domain_list.h
 smtp_sasl_glue.o: ../../include/dsn.h
 smtp_sasl_glue.o: ../../include/dsn_buf.h
 smtp_sasl_glue.o: ../../include/header_body_checks.h
@@ -636,6 +648,7 @@ smtp_sasl_proto.o: ../../include/check_arg.h
 smtp_sasl_proto.o: ../../include/deliver_request.h
 smtp_sasl_proto.o: ../../include/dict.h
 smtp_sasl_proto.o: ../../include/dns.h
+smtp_sasl_proto.o: ../../include/domain_list.h
 smtp_sasl_proto.o: ../../include/dsn.h
 smtp_sasl_proto.o: ../../include/dsn_buf.h
 smtp_sasl_proto.o: ../../include/header_body_checks.h
@@ -677,6 +690,7 @@ smtp_session.o: ../../include/debug_peer.h
 smtp_session.o: ../../include/deliver_request.h
 smtp_session.o: ../../include/dict.h
 smtp_session.o: ../../include/dns.h
+smtp_session.o: ../../include/domain_list.h
 smtp_session.o: ../../include/dsn.h
 smtp_session.o: ../../include/dsn_buf.h
 smtp_session.o: ../../include/header_body_checks.h
@@ -717,6 +731,7 @@ smtp_state.o: ../../include/debug_peer.h
 smtp_state.o: ../../include/deliver_request.h
 smtp_state.o: ../../include/dict.h
 smtp_state.o: ../../include/dns.h
+smtp_state.o: ../../include/domain_list.h
 smtp_state.o: ../../include/dsn.h
 smtp_state.o: ../../include/dsn_buf.h
 smtp_state.o: ../../include/header_body_checks.h
@@ -757,6 +772,7 @@ smtp_tls_policy.o: ../../include/ctable.h
 smtp_tls_policy.o: ../../include/deliver_request.h
 smtp_tls_policy.o: ../../include/dict.h
 smtp_tls_policy.o: ../../include/dns.h
+smtp_tls_policy.o: ../../include/domain_list.h
 smtp_tls_policy.o: ../../include/dsn.h
 smtp_tls_policy.o: ../../include/dsn_buf.h
 smtp_tls_policy.o: ../../include/header_body_checks.h
@@ -799,6 +815,7 @@ smtp_tlsrpt.o: ../../include/check_arg.h
 smtp_tlsrpt.o: ../../include/deliver_request.h
 smtp_tlsrpt.o: ../../include/dict.h
 smtp_tlsrpt.o: ../../include/dns.h
+smtp_tlsrpt.o: ../../include/domain_list.h
 smtp_tlsrpt.o: ../../include/dsn.h
 smtp_tlsrpt.o: ../../include/dsn_buf.h
 smtp_tlsrpt.o: ../../include/header_body_checks.h
@@ -843,6 +860,7 @@ smtp_trouble.o: ../../include/deliver_completed.h
 smtp_trouble.o: ../../include/deliver_request.h
 smtp_trouble.o: ../../include/dict.h
 smtp_trouble.o: ../../include/dns.h
+smtp_trouble.o: ../../include/domain_list.h
 smtp_trouble.o: ../../include/dsn.h
 smtp_trouble.o: ../../include/dsn_buf.h
 smtp_trouble.o: ../../include/header_body_checks.h
@@ -884,6 +902,7 @@ smtp_unalias.o: ../../include/check_arg.h
 smtp_unalias.o: ../../include/deliver_request.h
 smtp_unalias.o: ../../include/dict.h
 smtp_unalias.o: ../../include/dns.h
+smtp_unalias.o: ../../include/domain_list.h
 smtp_unalias.o: ../../include/dsn.h
 smtp_unalias.o: ../../include/dsn_buf.h
 smtp_unalias.o: ../../include/header_body_checks.h

postfix/src/smtp/lmtp_params.c

@@ -68,6 +68,7 @@
 	VAR_HFROM_FORMAT, DEF_HFROM_FORMAT, &var_hfrom_format, 1, 0,
 	VAR_USE_SRV_LOOKUP, DEF_USE_SRV_LOOKUP, &var_use_srv_lookup, 0, 0,
 	VAR_LMTP_TLSRPT_SOCKNAME, DEF_LMTP_TLSRPT_SOCKNAME, &var_smtp_tlsrpt_sockname, 0, 0,
+	VAR_LMTP_ENFORCE_REQUIRETLS, DEF_LMTP_ENFORCE_REQUIRETLS, &var_smtp_enforce_requiretls, 0, 0,
 	0,
     };
     static const CONFIG_TIME_TABLE lmtp_time_table[] = {

postfix/src/smtp/smtp.c

@@ -172,7 +172,7 @@
 /*	RFC 6531 (Internationalized SMTP)
 /*	RFC 6533 (Internationalized Delivery Status Notifications)
 /*	RFC 7672 (SMTP security via opportunistic DANE TLS)
-/*	RFC 8689 (TLS-Required message header)
+/*	RFC 8689 (SMTP REQUIRETLS extension)
 /* DIAGNOSTICS
 /*	Problems and transactions are logged to \fBsyslogd\fR(8)
 /*	or \fBpostlogd\fR(8).
@@ -453,7 +453,7 @@
 /* .IP "\fBsmtp_sasl_password_result_delimiter (:)\fR"
 /*	The delimiter between username and password in sasl_passwd_maps lookup
 /*	results.
-/* STARTTLS SUPPORT CONTROLS
+/* TLS SUPPORT CONTROLS
 /* .ad
 /* .fi
 /*	Detailed information about STARTTLS configuration may be found
@@ -653,7 +653,16 @@
 /* .IP "\fBtls_required_enable (yes)\fR"
 /*	Enable support for the "TLS-Required: no" message header, defined
 /*	in RFC 8689.
-/* OBSOLETE STARTTLS CONTROLS
+/* .IP "\fBrequiretls_enable (yes)\fR"
+/*	Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+/*	8689.
+/* .IP "\fBsmtp_enforce_requiretls (empty)\fR"
+/*	An optional list of next-hop destinations that the Postfix
+/*	SMTP/LMTP client will enforce REQUIRETLS for, when a message was
+/*	received with the REQUIRETLS option: the next-hop server must offer
+/*	a matching TLS server certificate, and the server must announce
+/*	REQUIRETLS support).
+/* OBSOLETE TLS CONTROLS
 /* .ad
 /* .fi
 /*	The following configuration parameters exist for compatibility
@@ -1020,6 +1029,8 @@
 #include <maps.h>
 #include <ext_prop.h>
 #include <hfrom_format.h>
+#include <domain_list.h>
+#include <match_parent_style.h>
 
 /* DNS library. */
 
@@ -1164,6 +1175,7 @@ bool    var_allow_srv_fallback;
 bool    var_smtp_tlsrpt_enable;
 char   *var_smtp_tlsrpt_sockname;
 bool    var_smtp_tlsrpt_skip_reused_hs;
+char   *var_smtp_enforce_requiretls;
 
  /* Special handling of 535 AUTH errors. */
 char   *var_smtp_sasl_auth_cache_name;
@@ -1191,6 +1203,7 @@ HBC_CHECKS *smtp_body_checks;		/* limited body checks */
 SMTP_CLI_ATTR smtp_cli_attr;		/* parsed command-line */
 int     smtp_hfrom_format;		/* postmaster notifications */
 STRING_LIST *smtp_use_srv_lookup;
+DOMAIN_LIST *smtp_enforce_requiretls;
 
 #ifdef USE_TLS
 
@@ -1698,6 +1711,23 @@ static void pre_init(char *unused_name, char **unused_argv)
     if (*var_smtp_dns_re_filter)
 	dns_rr_filter_compile(VAR_LMTP_SMTP(DNS_RE_FILTER),
 			      var_smtp_dns_re_filter);
+
+    /*
+     * REQUIRETLS enforcement uses a match list. No MATCH_FLAG_RETURN after
+     * table lookup error, because fail-open is not a good option. We would
+     * have to defer all delivery requests anyway. Disable /file/name magic
+     * for LMTP, because that would break the handling of UNIX-domain socket
+     * pathnames.
+     */
+    if (var_requiretls_enable && *var_smtp_enforce_requiretls) {
+	int     flags = smtp_mode ? 0 : MATCH_FLAG_NOFILE;
+	const char *param_name = VAR_LMTP_SMTP(ENFORCE_REQUIRETLS);
+
+	smtp_enforce_requiretls =
+	    domain_list_init(param_name,
+			     match_parent_style(param_name) | flags,
+			     var_smtp_enforce_requiretls);
+    }
 }
 
 /* pre_accept - see if tables have changed */

postfix/src/smtp/smtp.h

@@ -32,6 +32,7 @@
 #include <tok822.h>
 #include <dsn_buf.h>
 #include <header_body_checks.h>
+#include <domain_list.h>
 
  /*
   * Postfix TLS library.
@@ -210,6 +211,7 @@ typedef struct SMTP_STATE {
 #ifdef USE_TLSRPT
     struct TLSRPT_WRAPPER *tlsrpt;
 #endif
+    int enforce_requiretls;		/* from smtp_enforce_requiretls */
 #endif
 
     /*
@@ -296,6 +298,7 @@ typedef struct SMTP_STATE {
 #define SMTP_FEATURE_XFORWARD_IDENT	(1<<20)
 #define SMTP_FEATURE_SMTPUTF8		(1<<21)	/* RFC 6531 */
 #define SMTP_FEATURE_FROM_PROXY		(1<<22)	/* proxied connection */
+#define SMTP_FEATURE_REQUIRETLS		(1<<23)	/* RFC 8689 */
 
  /*
   * Features that passivate under the endpoint.
@@ -368,6 +371,7 @@ extern STRING_LIST *smtp_use_srv_lookup;/* services with SRV record lookup */
 
 extern TLS_APPL_STATE *smtp_tls_ctx;	/* client-side TLS engine */
 extern int smtp_tls_insecure_mx_policy;	/* DANE post insecure MX? */
+extern DOMAIN_LIST *smtp_enforce_requiretls;	/* parsed list */
 
 #endif
 
@@ -647,8 +651,9 @@ extern void smtp_rcpt_done(SMTP_STATE *, SMTP_RESP *, RECIPIENT *);
  /*
   * smtp_trouble.c
   */
-#define SMTP_THROTTLE	1
+#define SMTP_MISC_FAIL_NONE		0
-#define SMTP_NOTHROTTLE	0
+#define SMTP_MISC_FAIL_THROTTLE		(1<<0)
+#define SMTP_MISC_FAIL_SOFT_NON_FINAL	(1<<1)
 extern int smtp_sess_fail(SMTP_STATE *);
 extern int PRINTFLIKE(5, 6) smtp_misc_fail(SMTP_STATE *, int, const char *,
 				             SMTP_RESP *, const char *,...);
@@ -658,9 +663,9 @@ extern void PRINTFLIKE(5, 6) smtp_rcpt_fail(SMTP_STATE *, RECIPIENT *,
 extern int smtp_stream_except(SMTP_STATE *, int, const char *);
 
 #define smtp_site_fail(state, mta, resp, ...) \
-	smtp_misc_fail((state), SMTP_THROTTLE, (mta), (resp), __VA_ARGS__)
+    smtp_misc_fail((state), SMTP_MISC_FAIL_THROTTLE, (mta), (resp), __VA_ARGS__)
 #define smtp_mesg_fail(state, mta, resp, ...) \
-	smtp_misc_fail((state), SMTP_NOTHROTTLE, (mta), (resp), __VA_ARGS__)
+    smtp_misc_fail((state), SMTP_MISC_FAIL_NONE, (mta), (resp), __VA_ARGS__)
 
  /*
   * smtp_unalias.c

postfix/src/smtp/smtp_connect.c

@@ -106,6 +106,7 @@
 #include <mail_addr.h>
 #include <valid_hostname.h>
 #include <sendopts.h>
+#include <domain_list.h>
 
 /* DNS library. */
 
@@ -533,19 +534,32 @@ static int smtp_get_effective_tls_level(DSN_BUF *why, SMTP_STATE *state)
     }
 
     /*
-     * If the sender requires verified TLS, the TLS level must enforce a
+     * If the sender requires TLS with server certificate verification, the
-     * server certificate match.
+     * TLS level must enforce a server certificate match.
      */
-#if 0
+    else if (var_requiretls_enable
-    else if ((state->request->sendopts & SOPT_REQUIRETLS_ESMTP)) {
+	     && (state->request->sendopts & SOPT_REQUIRETLS_ESMTP)) {
 	if (TLS_MUST_MATCH(tls->level) == 0) {
-	    dsb_simple(why, "5.7.10", "Sender requires verified TLS, "
+	    if (state->enforce_requiretls) {
-		       " but my configured TLS security level is '%s %s'",
+		dsb_simple(why, "5.7.10", "REQUIRETLS Failure: Sender "
-		       var_mail_name, str_tls_level(tls->level));
+			   "requires a TLS server certificate match, "
-	    return (0);
+			   "but the configured %s TLS security level '%s' "
+			   "does not support that. The last attempted "
+			   "server was %s",
+			   var_mail_name, str_tls_level(tls->level),
+			   STR(iter->host));
+		return (0);
+	    } else {
+		msg_info("REQUIRETLS Debug: Sender requires a TLS server "
+			 "certificate match, but the configured %s TLS "
+			 "security level '%s' does not support that. "
+			 "The last attempted server was %s",
+			 var_mail_name, str_tls_level(tls->level),
+			 STR(iter->host));
+		return (0);
+	    }
 	}
     }
-#endif
 
     /*
      * Success.
@@ -582,6 +596,18 @@ static void smtp_connect_local(SMTP_STATE *state, const char *path)
     if (state->misc_flags & SMTP_MISC_FLAG_CONN_CACHE_MASK)
 	SET_SCACHE_REQUEST_NEXTHOP(state, path);
 
+    /*
+     * REQUIRETLS enforcement is based on the UNIX-domain pathname, without
+     * the "unix:" prefix.
+     */
+#ifdef USE_TLS
+    state->enforce_requiretls =
+	(var_requiretls_enable
+	 && smtp_enforce_requiretls
+	 && (state->request->sendopts & SOPT_REQUIRETLS_ESMTP) != 0
+	 && domain_list_match(smtp_enforce_requiretls, path));
+#endif
+
     /*
      * Here we ensure that the iter->addr member refers to a copy of the
      * UNIX-domain pathname, so that smtp_save_session() will cache the
@@ -986,6 +1012,18 @@ static void smtp_connect_inet(SMTP_STATE *state, const char *nexthop,
 	    state->tlsrpt = 0;
 #endif						/* USE_TLSRPT */
 
+	/*
+	 * REQUIRETLS enforcement is based on the next-hop domain name
+	 * without the service or port.
+	 */
+#ifdef USE_TLS
+	state->enforce_requiretls =
+	    (var_requiretls_enable
+	     && smtp_enforce_requiretls
+	     && (state->request->sendopts & SOPT_REQUIRETLS_ESMTP) != 0
+	     && domain_list_match(smtp_enforce_requiretls, domain));
+#endif
+
 	/*
 	 * Resolve an SMTP or LMTP server. Skip MX or SRV lookups when a
 	 * quoted domain is specified or when DNS lookups are disabled.

postfix/src/smtp/smtp_params.c

@@ -69,6 +69,7 @@
 	VAR_HFROM_FORMAT, DEF_HFROM_FORMAT, &var_hfrom_format, 1, 0,
 	VAR_USE_SRV_LOOKUP, DEF_USE_SRV_LOOKUP, &var_use_srv_lookup, 0, 0,
 	VAR_SMTP_TLSRPT_SOCKNAME, DEF_SMTP_TLSRPT_SOCKNAME, &var_smtp_tlsrpt_sockname, 0, 0,
+	VAR_SMTP_ENFORCE_REQUIRETLS, DEF_SMTP_ENFORCE_REQUIRETLS, &var_smtp_enforce_requiretls, 0, 0,
 	0,
     };
     static const CONFIG_TIME_TABLE smtp_time_table[] = {

postfix/src/smtp/smtp_proto.c

@@ -604,6 +604,10 @@ int     smtp_helo(SMTP_STATE *state)
 		    /* Ignored later if we already sent STARTTLS. */
 		    if ((discard_mask & EHLO_MASK_STARTTLS) == 0)
 			session->features |= SMTP_FEATURE_STARTTLS;
+		} else if (strcasecmp(word, "REQUIRETLS") == 0) {
+		    if ((discard_mask & EHLO_MASK_REQUIRETLS) == 0
+			&& (state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS))
+			session->features |= SMTP_FEATURE_REQUIRETLS;
 #endif
 #ifdef USE_SASL_AUTH
 		} else if (var_smtp_sasl_enable
@@ -661,7 +665,8 @@ int     smtp_helo(SMTP_STATE *state)
      */
     if ((session->features & SMTP_FEATURE_SMTPUTF8) == 0
 	&& DELIVERY_REQUIRES_SMTPUTF8)
-	return (smtp_mesg_fail(state, DSN_BY_LOCAL_MTA,
+	return (smtp_misc_fail(state, SMTP_MISC_FAIL_SOFT_NON_FINAL,
+			       DSN_BY_LOCAL_MTA,
 			       SMTP_RESP_FAKE(&fake, "5.6.7"),
 			       "SMTPUTF8 is required, "
 			       "but was not offered by host %s",
@@ -679,6 +684,35 @@ int     smtp_helo(SMTP_STATE *state)
 	session->features |= SMTP_FEATURE_8BITMIME;
     }
 
+    /*
+     * Require that the server announces REQUIRETLS when the sender requested
+     * REQUIRETLS. Return the message as undeliverable only when there are no
+     * more alternative MX hosts.
+     */
+#ifdef USE_TLS
+    if (var_requiretls_enable
+	&& (request->sendopts & SOPT_REQUIRETLS_ESMTP) != 0
+	&& (state->misc_flags & SMTP_MISC_FLAG_IN_STARTTLS) != 0
+	&& (session->features & SMTP_FEATURE_REQUIRETLS) == 0) {
+	if (state->enforce_requiretls) {
+	    return (smtp_misc_fail(state, SMTP_MISC_FAIL_SOFT_NON_FINAL,
+				   DSN_BY_LOCAL_MTA,
+				   SMTP_RESP_FAKE(&fake, "5.7.30"),
+				   "REQUIRETLS Failure: Sender requested "
+				   "delivery wth REQUIRETLS, but no mail "
+				   "server was found with REQUIRETLS "
+				   "support. The last attempted server "
+				   "was %s", session->namaddr));
+	} else {
+	    msg_info("REQUIRETLS Debug: Sender requested delivery wth "
+		     "REQUIRETLS, but no mail server was found with "
+		     "REQUIRETLS support. The last attempted server was "
+		     "%s", session->namaddr);
+	}
+
+    }
+#endif
+
     /*
      * We use SMTP command pipelining if the server said it supported it.
      * Since we use blocking I/O, RFC 2197 says that we should inspect the
@@ -1146,7 +1180,7 @@ static int smtp_start_tls(SMTP_STATE *state)
 	if (PLAINTEXT_FALLBACK_OK_AFTER_STARTTLS_FAILURE)
 	    RETRY_AS_PLAINTEXT;
 	return (smtp_misc_fail(state, state->tls->level == TLS_LEV_MAY ?
-			       SMTP_NOTHROTTLE : SMTP_THROTTLE,
+			       SMTP_MISC_FAIL_NONE : SMTP_MISC_FAIL_THROTTLE,
 			       DSN_BY_LOCAL_MTA,
 			       SMTP_RESP_FAKE(&fake, "4.7.5"),
 			       "Cannot start TLS: handshake failure"));
@@ -1191,6 +1225,31 @@ static int smtp_start_tls(SMTP_STATE *state)
 		}
 	    }
 #endif
+
+	    /*
+	     * Require a server certificate match when the sender requested
+	     * REQUIRETLS. Return the message as undeliverable only when
+	     * there are no more alternative MX hosts.
+	     */
+	    if (var_requiretls_enable
+		&& (state->request->sendopts & SOPT_REQUIRETLS_ESMTP)) {
+		if (state->enforce_requiretls) {
+		    return (smtp_misc_fail(state, SMTP_MISC_FAIL_SOFT_NON_FINAL,
+					   DSN_BY_LOCAL_MTA,
+					   SMTP_RESP_FAKE(&fake, "5.7.10"),
+					   "REQUIRETLS Failure: Sender "
+					   "requested a TLS server "
+					   "certificate match, but no "
+					   "match was found. The last "
+					   "attempted server was %s",
+					   session->namaddr));
+		} else {
+		    msg_info("REQUIRETLS Debug: Sender requested a TLS "
+			     "server certificate match, but no match was "
+			     "found. The last attempted server was %s",
+			     session->namaddr);
+		}
+	    }
 	    return (smtp_site_fail(state, DSN_BY_LOCAL_MTA,
 				   SMTP_RESP_FAKE(&fake, "4.7.5"),
 				   "Server certificate not verified"));
@@ -1781,7 +1840,22 @@ static int smtp_loop(SMTP_STATE *state, NOCLOBBER int send_state,
 	    if ((session->features & SMTP_FEATURE_SMTPUTF8) != 0
 		&& (request->sendopts & SMTPUTF8_FLAG_REQUESTED) != 0)
 		vstring_strcat(next_command, " SMTPUTF8");
-	    /* TODO(wietse) REQUIRETLS. */
+
+	    /*
+	     * Request REQUIRETLS when the remote SMTP server supports
+	     * REQUIRETLS and the sender requested REQUIRETLS.
+	     */
+#ifdef USE_TLS
+	    if (var_requiretls_enable
+		&& (request->sendopts & SOPT_REQUIRETLS_ESMTP) != 0) {
+		if ((session->features & SMTP_FEATURE_REQUIRETLS) != 0)
+		    vstring_strcat(next_command, " REQUIRETLS");
+		else if (state->enforce_requiretls)
+		    msg_panic("Can't happen: must enforce REQUIRETLS, but "
+			      "host %s did not announce REQUIRETLS support",
+			      session->namaddr);
+	    }
+#endif
 
 	    /*
 	     * We authenticate the local MTA only, but not the sender.

postfix/src/smtp/smtp_state.c

@@ -82,6 +82,9 @@ SMTP_STATE *smtp_state_alloc(void)
     state->iterator->saved_dest = vstring_alloc(100);
 #ifdef USE_TLSRPT
     state->tlsrpt = 0;
+#endif
+#ifdef USE_TLS
+    state->enforce_requiretls = 0;
 #endif
     if (var_smtp_cache_conn) {
 	state->dest_label = vstring_alloc(10);

postfix/src/smtp/smtp_trouble.c

@@ -33,9 +33,9 @@
 /*	int	exception;
 /*	const char *description;
 /* AUXILIARY FUNCTIONS
-/*	int	smtp_misc_fail(state, throttle, mta_name, resp, format, ...)
+/*	int	smtp_misc_fail(state, flags, mta_name, resp, format, ...)
 /*	SMTP_STATE *state;
-/*	int	throttle;
+/*	int	flags;
 /*	const char *mta_name;
 /*	SMTP_RESP *resp;
 /*	const char *format;
@@ -91,8 +91,11 @@
 /*
 /*	smtp_misc_fail() provides a more detailed interface than
 /*	smtp_site_fail() and smtp_mesg_fail(), which are convenience
-/*	wrappers around smtp_misc_fail(). The throttle argument
+/*	wrappers around smtp_misc_fail(). The flags argument is either
-/*	is either SMTP_THROTTLE or SMTP_NOTHROTTLE; it is used only
+/*	SMTP_MISC_FAIL_NONE or the bitwise OR of SMTP_MISC_FAIL_THROTTLE
+/*	(throttle the destination) and/or SMTP_MISC_FAIL_SOFT_NON_FINAL
+/*	(if the server was not the last one to try, treat a hard error
+/*	as a soft error); SMTP_MISC_FAIL_THROTTLE is used only
 /*	in the "soft error, final server" policy, and determines
 /*	whether a destination will be marked as problematic.
 /*
@@ -210,7 +213,7 @@ static void smtp_check_code(SMTP_SESSION *session, int code)
 
 /* smtp_bulk_fail - skip, defer or bounce recipients, maybe throttle queue */
 
-static int smtp_bulk_fail(SMTP_STATE *state, int throttle_queue)
+static int smtp_bulk_fail(SMTP_STATE *state, int flags)
 {
     DELIVER_REQUEST *request = state->request;
     SMTP_SESSION *session = state->session;
@@ -220,8 +223,21 @@ static int smtp_bulk_fail(SMTP_STATE *state, int throttle_queue)
     int     aggregate_status;
     int     soft_error = (STR(why->status)[0] == '4');
     int     soft_bounce_error = (STR(why->status)[0] == '5' && var_soft_bounce);
+    int     throttle_queue = (flags & SMTP_MISC_FAIL_THROTTLE);
     int     nrcpt;
 
+    /*
+     * Sanity check.
+     */
+    if ((flags & SMTP_MISC_FAIL_SOFT_NON_FINAL) != 0) {
+	if (soft_error) {
+	    msg_warn("smtp_bulk_fail: ignoring SMTP_MISC_FAIL_SOFT_NON_FINAL "
+		    "for a soft error");
+	} else {
+	    soft_error = (state->misc_flags & SMTP_MISC_FLAG_FINAL_SERVER) == 0;
+	}
+    }
+
     /*
      * Don't defer the recipients just yet when this error qualifies them for
      * delivery to a backup server. Just log something informative to show
@@ -302,7 +318,7 @@ int     smtp_sess_fail(SMTP_STATE *state)
      * because this error information is collected by a routine that
      * terminates BEFORE the error is reported.
      */
-    return (smtp_bulk_fail(state, SMTP_THROTTLE));
+    return (smtp_bulk_fail(state, SMTP_MISC_FAIL_THROTTLE));
 }
 
 /* vsmtp_fill_dsn - fill in temporary DSN structure */
@@ -342,7 +358,7 @@ static void vsmtp_fill_dsn(SMTP_STATE *state, const char *mta_name,
 
 /* smtp_misc_fail - maybe throttle queue; skip/defer/bounce all recipients */
 
-int     smtp_misc_fail(SMTP_STATE *state, int throttle, const char *mta_name,
+int     smtp_misc_fail(SMTP_STATE *state, int flags, const char *mta_name,
 		               SMTP_RESP *resp, const char *format,...)
 {
     va_list ap;
@@ -360,7 +376,7 @@ int     smtp_misc_fail(SMTP_STATE *state, int throttle, const char *mta_name,
     /*
      * Skip, defer or bounce recipients, and throttle this queue.
      */
-    return (smtp_bulk_fail(state, throttle));
+    return (smtp_bulk_fail(state, flags));
 }
 
 /* smtp_rcpt_fail - skip, defer, or bounce recipient */
@@ -472,5 +488,5 @@ int     smtp_stream_except(SMTP_STATE *state, int code, const char *description)
      * falling back to plaintext, because RETRY_AS_PLAINTEXT clears the
      * FINAL_SERVER flag.
      */
-    return (smtp_bulk_fail(state, SMTP_THROTTLE));
+    return (smtp_bulk_fail(state, SMTP_MISC_FAIL_THROTTLE));
 }

postfix/src/smtpd/smtpd.c

@@ -57,6 +57,7 @@
 /*	RFC 6531 (Internationalized SMTP)
 /*	RFC 6533 (Internationalized Delivery Status Notifications)
 /*	RFC 7505 ("Null MX" No Service Resource Record)
+/*	RFC 8689 (SMTP REQUIRETLS extension)
 /* DIAGNOSTICS
 /*	Problems and transactions are logged to \fBsyslogd\fR(8)
 /*	or \fBpostlogd\fR(8).
@@ -370,7 +371,7 @@
 /* .IP "\fBsmtpd_sasl_mechanism_filter (!external, static:rest)\fR"
 /*	If non-empty, a filter for the SASL mechanism names that the
 /*	Postfix SMTP server will announce in the EHLO response.
-/* STARTTLS SUPPORT CONTROLS
+/* TLS SUPPORT CONTROLS
 /* .ad
 /* .fi
 /*	Detailed information about STARTTLS configuration may be
@@ -544,7 +545,12 @@
 /*	Request that remote SMTP clients send an RFC7250 raw public key
 /*	instead of an X.509 certificate, when asking for or requiring client
 /*	authentication.
-/* OBSOLETE STARTTLS CONTROLS
+/* .PP
+/*	Available in Postfix version 3.10 and later:
+/* .IP "\fBrequiretls_enable (yes)\fR"
+/*	Enable support for the ESMTP verb "REQUIRETLS", defined in RFC
+/*	8689.
+/* OBSOLETE TLS CONTROLS
 /* .ad
 /* .fi
 /*	The following configuration parameters exist for compatibility
@@ -2105,6 +2111,11 @@ static int ehlo_cmd(SMTPD_STATE *state, int argc, SMTPD_TOKEN *argv)
 	EHLO_APPEND(state, "SMTPUTF8");
     if ((discard_mask & EHLO_MASK_CHUNKING) == 0)
 	EHLO_APPEND(state, "CHUNKING");
+#ifdef USE_TLS
+    if (var_requiretls_enable && (discard_mask & EHLO_MASK_REQUIRETLS) == 0
+	&& state->tls_context != 0)
+	EHLO_APPEND(state, "REQUIRETLS");
+#endif
 
     /*
      * Send the reply.
@@ -2219,7 +2230,8 @@ static int mail_open_stream(SMTPD_STATE *state)
 	    cleanup_flags |= CLEANUP_FLAG_SMTPUTF8;
 	else
 	    cleanup_flags |= smtputf8_autodetect(MAIL_SRC_MASK_SMTPD);
-	/* TODO(wietse) REQUIRETLS. */
+	if (state->flags & SMTPD_FLAG_REQUIRETLS)
+	    cleanup_flags |= CLEANUP_FLAG_REQUIRETLS;
 	state->dest = mail_stream_service(MAIL_CLASS_PUBLIC,
 					  var_cleanup_service);
 	if (state->dest == 0
@@ -2679,6 +2691,13 @@ static int mail_cmd(SMTPD_STATE *state, int argc, SMTPD_TOKEN *argv)
 		   && (state->ehlo_discard_mask & EHLO_MASK_SMTPUTF8) == 0
 		   && strcasecmp(arg, "SMTPUTF8") == 0) {	/* RFC 6531 */
 	     /* Already processed early. */ ;
+#ifdef USE_TLS
+	} else if (var_requiretls_enable
+		   && state->tls_context != 0
+		   && (state->ehlo_discard_mask & EHLO_MASK_REQUIRETLS) == 0
+		   && strcasecmp(arg, "REQUIRETLS") == 0) {	/* RFC 8689 */
+	    state->flags |= SMTPD_FLAG_REQUIRETLS;
+#endif
 #ifdef USE_SASL_AUTH
 	} else if (strncasecmp(arg, "AUTH=", 5) == 0) {
 	    if ((err = smtpd_sasl_mail_opt(state, arg + 5)) != 0) {

postfix/src/smtpd/smtpd.h

@@ -209,6 +209,7 @@ typedef struct {
 #define SMTPD_FLAG_AUTH_USED	   (1<<2)	/* don't reuse SASL state */
 #define SMTPD_FLAG_SMTPUTF8	   (1<<3)	/* RFC 6531/2 transaction */
 #define SMTPD_FLAG_NEED_MILTER_ABORT (1<<4)	/* undo milter_mail_event() */
+#define SMTPD_FLAG_REQUIRETLS	   (1<<5)	/* RFC 8689 */
 
 #define SMTPD_NOTE_BARE_LF	   (1<<0)	/* saw at least one bare LF */
 

postfix/src/util/match_list.c

@@ -60,6 +60,10 @@
 /*	Request that match_list_match() logs a warning and returns
 /*	zero (with list->error set to a non-zero dictionary error
 /*	code) instead of raising a fatal run-time error.
+/* .IP MATCH_FLAG_NOFILE
+/*	Disable special handling for /file/name.
+/* .IP MATCH_FLAG_NODICT
+/*	Disable special handling for type:name.
 /* .RE
 /*	Specify MATCH_FLAG_NONE to request none of the above.
 /* .IP pattern_list
@@ -84,6 +88,9 @@
 /*	IBM T.J. Watson Research
 /*	P.O. Box 704
 /*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	porcupine.org
 /*--*/
 
 /* System library. */
@@ -151,7 +158,8 @@ static ARGV *match_list_parse(MATCH_LIST *match_list, ARGV *pat_list,
 	if (*item == 0)
 	    /* No graceful degradation for this... */
 	    msg_fatal("%s: no pattern after '!'", match_list->pname);
-	if (*item == '/') {			/* /file/name */
+	if (*item == '/'			/* /file/name */
+	    && (match_list->flags & MATCH_FLAG_NOFILE) == 0) {
 	    if ((fp = vstream_fopen(item, O_RDONLY, 0)) == 0) {
 		/* Replace unusable pattern with pseudo table. */
 		vstring_sprintf(buf, "%s:%s", DICT_TYPE_NOFILE, item);
@@ -168,7 +176,8 @@ static ARGV *match_list_parse(MATCH_LIST *match_list, ARGV *pat_list,
 		if (vstream_fclose(fp))
 		    msg_fatal("%s: read file %s: %m", myname, item);
 	    }
-	} else if (MATCH_DICTIONARY(item)) {	/* type:table */
+	} else if (MATCH_DICTIONARY(item)	/* type:table */
+		   &&(match_list->flags & MATCH_FLAG_NODICT) == 0) {
 	    vstring_sprintf(buf, "%s%s", match ? "" : "!",
 			 dict_open(item, OPEN_FLAGS, DICT_FLAGS)->reg_name);
 	    argv_add(pat_list, STR(buf), (char *) 0);

postfix/src/util/match_list.h

@@ -38,8 +38,10 @@ struct MATCH_LIST {
 #define MATCH_FLAG_NONE		0
 #define MATCH_FLAG_PARENT	(1<<0)
 #define MATCH_FLAG_RETURN	(1<<1)
-#define MATCH_FLAG_ALL		(MATCH_FLAG_PARENT | MATCH_FLAG_RETURN)
+#define MATCH_FLAG_NOFILE	(1<<2)
-
+#define MATCH_FLAG_NODICT	(1<<3)
+#define MATCH_FLAG_ALL		(MATCH_FLAG_PARENT | MATCH_FLAG_RETURN | \
+				MATCH_FLAG_NOFILE | MATCH_FLAG_NODICT)
 extern MATCH_LIST *match_list_init(const char *, int, const char *, int,...);
 extern int match_list_match(MATCH_LIST *,...);
 extern void match_list_free(MATCH_LIST *);