mir/postfix
2
0
Fork 0
mirror of https://github.com/vdukhovni/postfix synced 2025-08-30 21:55:20 +00:00
Code Issues Releases Wiki Activity

postfix-2.9-20110116

Browse Source
This commit is contained in:
Wietse Venema
2011-01-16 00:00:00 -05:00
committed by Viktor Dukhovni
parent ee84c57d75
commit b9df75b70d
18 changed files with 835 additions and 701 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
postfix/HISTORY
View File

@@ -16457,3 +16457,17 @@ Apologies for any names omitted.
now configurable, in case someone needs this. Files: now configurable, in case someone needs this. Files:
global/mail_params.h, postscreen/postscreen.c, mantools/postlink, global/mail_params.h, postscreen/postscreen.c, mantools/postlink,
proto/postconf.proto. proto/postconf.proto.
20110116
Cleanup: soft_bounce support for postscreen(8). Files:
postscreen/postscreen_smtpd.c, postscreen/postscreen_send.c.
Cleanup: for smtpd(8) compatibility, postscreen(8) now
strips deprecated route address prefixes from email addresses
(@here,@there:user@example becomes user@example). This is
primarily to make postscreen(8) logging more similar to
that of smtpd(8). File: postscreen/postscreen_smtpd.c.
Cleanup: documentation, in preparation for the Postfix 2.8
stable release.

59
postfix/README_FILES/POSTSCREEN_README
View File

@@ -13,15 +13,14 @@ postscreen(8) should not be used on SMTP ports that receive mail from end-user
clients (MUAs). In a typical deployment, postscreen(8) is used on the "port 25" clients (MUAs). In a typical deployment, postscreen(8) is used on the "port 25"
service, while MUA clients submit mail via the submission service. service, while MUA clients submit mail via the submission service.
postscreen(8) is the first layer in a multi-layer defense. postscreen(8) is part of a multi-layer defense.
* The postscreen(8) layer blocks connections from zombies and other spambots * As the first layer, postscreen(8) blocks connections from zombies and other
that are responsible for about 90% of all spam. It is implemented as a spambots that are responsible for about 90% of all spam. It is implemented
single process to make this defense as cheap as possible. as a single process to make this defense as cheap as possible.
* The second layer implements more complex SMTP-level access checks that are * The second layer implements more complex SMTP-level access checks with
available with Postfix SMTP servers, policy daemons, and Milter Postfix SMTP servers, policy daemons, and Milter applications.
applications.
* The third layer performs light-weight content inspection with the Postfix * The third layer performs light-weight content inspection with the Postfix
built-in header_checks and body_checks. This can block unacceptable built-in header_checks and body_checks. This can block unacceptable
@@ -482,14 +481,29 @@ TTuurrnniinngg oonn ppoossttssccrreeeenn((88)) wwiitth
To enable the postscreen(8) service and log client information without blocking To enable the postscreen(8) service and log client information without blocking
mail: mail:
1. Comment out the "smtp inet ... smtpd" service in master.cf, including any 1. Make sure that local clients and systems with non-standard SMTP
implementations are excluded from any postscreen(8) tests. The default is
to exclude all clients in mynetworks. To exclude additional clients, for
example, third-party performance monitoring tools (these tend to have
broken SMTP implementations):
/etc/postfix/main.cf:
# Exclude broken clients by whitelisting. Clients in mynetworks
# should always be whitelisted.
postscreen_access_list = permit_mynetworks,
cidr:/etc/postfix/postscreen_access.cidr
/etc/postfix/postscreen_access.cidr:
192.168.254.0/24 permit
2. Comment out the "smtp inet ... smtpd" service in master.cf, including any
"-o parameter=value" entries that follow. "-o parameter=value" entries that follow.
/etc/postfix/master.cf: /etc/postfix/master.cf:
#smtp inet n - n - - smtpd #smtp inet n - n - - smtpd
# -o parameter=value ... # -o parameter=value ...
2. Uncomment the new "smtpd pass ... smtpd" service in master.cf, and 3. Uncomment the new "smtpd pass ... smtpd" service in master.cf, and
duplicate any "-o parameter=value" entries from the smtpd service that was duplicate any "-o parameter=value" entries from the smtpd service that was
commented out in step 1. commented out in step 1.
@@ -497,24 +511,24 @@ mail:
smtpd pass - - n - - smtpd smtpd pass - - n - - smtpd
-o parameter=value ... -o parameter=value ...
3. Uncomment the new "smtp inet ... postscreen" service in master.cf. 4. Uncomment the new "smtp inet ... postscreen" service in master.cf.
/etc/postfix/master.cf: /etc/postfix/master.cf:
smtp inet n - n - 1 postscreen smtp inet n - n - 1 postscreen
4. Uncomment the new "tlsproxy unix ... tlsproxy" service in master.cf. This 5. Uncomment the new "tlsproxy unix ... tlsproxy" service in master.cf. This
service implements STARTTLS support for postscreen(8). service implements STARTTLS support for postscreen(8).
/etc/postfix/master.cf: /etc/postfix/master.cf:
tlsproxy unix - - n - 0 tlsproxy tlsproxy unix - - n - 0 tlsproxy
5. Uncomment the new "dnsblog unix ... dnsblog" service in master.cf. This 6. Uncomment the new "dnsblog unix ... dnsblog" service in master.cf. This
service does DNSBL lookups for postscreen(8) and logs results. service does DNSBL lookups for postscreen(8) and logs results.
/etc/postfix/master.cf: /etc/postfix/master.cf:
dnsblog unix - - n - 0 dnsblog dnsblog unix - - n - 0 dnsblog
6. To enable DNSBL lookups, list some DNS blocklist sites in main.cf, 7. To enable DNSBL lookups, list some DNS blocklist sites in main.cf,
separated by whitespace. Different sites can have different weights. For separated by whitespace. Different sites can have different weights. For
example: example:
@@ -537,7 +551,7 @@ mail:
run postmap(1) before the file can be used, and that it does not detect run postmap(1) before the file can be used, and that it does not detect
changes after the file is read. It is new with Postfix version 2.8. changes after the file is read. It is new with Postfix version 2.8.
7. Read the new configuration with "postfix reload". 8. Read the new configuration with "postfix reload".
Notes: Notes:
@@ -549,9 +563,6 @@ Notes:
* See "Tests before the 220 SMTP server greeting" for details about the * See "Tests before the 220 SMTP server greeting" for details about the
logging from these postscreen(8) tests. logging from these postscreen(8) tests.
* By default, postscreen(8) whitelists all clients in mynetworks. This is a
safety feature to avoid you from getting into trouble with local users.
* If you run Postfix 2.6 or earlier you must stop and start the master daemon * If you run Postfix 2.6 or earlier you must stop and start the master daemon
("postfix stop; postfix start"). This is needed because the Postfix "pass" ("postfix stop; postfix start"). This is needed because the Postfix "pass"
master service type did not work reliably on all systems. master service type did not work reliably on all systems.
@@ -575,6 +586,20 @@ those same parameter overrides for the postscreen(8) and tlsproxy(8) services.
BBlloocckkiinngg mmaaiill wwiitthh ppoossttssccrreeeenn((88)) BBlloocckkiinngg mmaaiill wwiitthh ppoossttssccrreeeenn((88))
For compatibility with smtpd(8), postscreen(8) implements the soft_bounce
safety feature. This causes Postfix to reject mail with a "try again" reply
code.
* To turn this on for all of Postfix, specify "soft_bounce = yes" in main.cf.
* To turn this on for postscreen(8) only, append "-o soft_bounce=yes" (note:
NO SPACES around '=') to the postscreen entry in master.cf.
Execute "postfix reload" to make the change effective.
After testing, do not forget to remove the soft_bounce feature, otherwise
senders won't receive their non-delivery notification until many days later.
To use the postscreen(8) service to block mail, edit main.cf and specify one or To use the postscreen(8) service to block mail, edit main.cf and specify one or
more of: more of:

426
postfix/RELEASE_NOTES
View File

@@ -1,433 +1,15 @@
The stable Postfix release is called postfix-2.7.x where 2=major The stable Postfix release is called postfix-2.8.x where 2=major
release number, 7=minor release number, x=patchlevel. The stable release number, 8=minor release number, x=patchlevel. The stable
release never changes except for patches that address bugs or release never changes except for patches that address bugs or
emergencies. Patches change the patchlevel and the release date. emergencies. Patches change the patchlevel and the release date.
New features are developed in snapshot releases. These are called New features are developed in snapshot releases. These are called
postfix-2.8-yyyymmdd where yyyymmdd is the release date (yyyy=year, postfix-2.9-yyyymmdd where yyyymmdd is the release date (yyyy=year,
mm=month, dd=day). Patches are never issued for snapshot releases; mm=month, dd=day). Patches are never issued for snapshot releases;
instead, a new snapshot is released. instead, a new snapshot is released.
The mail_release_date configuration parameter (format: yyyymmdd) The mail_release_date configuration parameter (format: yyyymmdd)
specifies the release date of a stable release or snapshot release. specifies the release date of a stable release or snapshot release.
If you upgrade from Postfix 2.6 or earlier, read RELEASE_NOTES-2.7 If you upgrade from Postfix 2.7 or earlier, read RELEASE_NOTES-2.8
before proceeding. before proceeding.
Postscreen notes:
=================
To turn on postscreen, see "Configuring the postscreen(8) service"
in the POSTSCREEN_README file. This allows you to run postscreen
without blocking mail first.
The code is rock solid, but the user interface has dozens of
parameters, so it literally is like using a machine that has wires
hanging out on all sides. This makes it possible to do research.
The idea is to reduce the number of parameters once things settle
down.
NOTE: Some postscreen parameters implement stress-dependent behavior.
This is supported only when the default value is stress-dependent
(that is, the default looks like ${stress?XX}${stress:YY}, or it
is the $name of an smtpd_xxx parameter with a stress-dependent
default). Other postscreen parameters always evaluate as if the
stress value is equal to the empty string.
Incompatibility with snapshot 20110111
======================================
For performance reasons the postscreen_access_list feature replaces
the postscreen_whitelist_networks and postscreen_blacklist_networks
features. CIDR-style access maps are some 100x faster than the code
that implemented the postscreen_white/blacklist_networks support.
It can match about 100 million CIDR patterns/second on a modern CPU,
which is not blindingly fast but adequate for the near future.
Major changes with snapshot 20110105
====================================
The SMTP server now supports contact information that is appended
to "reject" responses. This includes SMTP server responses that
aren't logged to the maillog file, such as responses to syntax
errors, or unsupported commands.
Example:
smtpd_reject_footer = For assistance, call 800-555-0101.
Server response:
550-5.5.1 <user@example> Recipient address rejected: User unknown
550 5.5.1 For assistance, call 800-555-0101.
This feature supports macro expansion ($client_address, $localtime,
etc.), as documented in the postconf(5) manpage.
This feature is also supported as postscreen_reject_footer using
the same setting as smtpd_reject_footer by default.
Incompatibility with snapshot 20110102
======================================
The smtpd_starttls_timeout default value is now stress-dependent.
By default, TLS negotiations must now complete under overload in
10s instead of 300s.
The Postfix SMTP server now always re-computes the SASL mechanism
list after successful completion of the STARTTLS command. Earlier
versions only re-computed the mechanism list when the values of
smtp_sasl_tls_security_options and smtp_sasl_security_options differ.
This could produce incorrect results, because the Dovecot authentication
server may change responses when the SMTP session is encrypted.
Major changes with snapshot 20110102
====================================
STARTTLS support for the postscreen(8) daemon. This is implemented
by a new tlsproxy(8) daemon that you will need to enable in master.cf
(see POSTSCREEN_README for instructions). tlsproxy(8) implements
its own tlsproxy_mumble versions of TLS-related smtpd_mumble
parameters. This leaves no confusion about which parameters will
affect tlsproxy(8) behavior, but it adds another 25 parameters to
the documentation.
Major changes with snapshot 20101223
====================================
The new tls_disable_workarounds parameter specifies a list or
bit-mask of OpenSSL bug work-arounds to disable. This may be necessary
if one of the work-arounds enabled by default in OpenSSL proves to
pose a security risk, or introduces an unexpected interoperability
issue. Some bug work-arounds known to be problematic are disabled
in the default value of the parameter when linked with an OpenSSL
library that could be vulnerable. See postconf(5) and TLS_README
for details.
With "tls_preempt_cipherlist = yes" the Postfix SMTP server will
choose its most preferred cipher that is supported (offered) by the
client. This can lead to a more secure or performant cipher choice,
but may also introduce interoperability problems when a client
announces support for a cipher that does not work. See postconf(5)
and TLS_README for details.
Major changes with snapshot 20101217
====================================
The lower-level code in the TLS engine was simplified by removing
an unnecessary layer of data copying. OpenSSL now writes directly
to the network. The difference in performance should be hardly
noticeable.
Incompatibility with snapshot 20101206
======================================
Postfix by default no longer adds a "To: undisclosed-recipients:;"
header when no recipient specified in the message header. The
Internet mail RFCs have supported messages without recipient header
for almost 10 years now.
For backwards compatibility, specify:
/etc/postfix/main.cf
undisclosed_recipients_header = To: undisclosed-recipients:;
Note: both the ":" and ";" are required.
Incompatibility with snapshot 20101202
======================================
Postfix now reports a temporary delivery error when the result of
virtual alias expansion would exceed the virtual_alias_recursion_limit
or virtual_alias_expansion_limit. Previously, Postfix would silently
drop the excess recipients and deliver the message.
Incompatibility with snapshot 20101130
======================================
The postscreen(8) daemon now logs the client as [address]:port.
The port helps to distinguish between simultaneous sessions from
the same address, and the [] allow the same tool to be used with
old and new format logfiles, without producing errors for IPv6.
Major changes with snapshot 20101126
====================================
Support for address patterns in DNSBL and DNSWL lookup results.
For example, "reject_rbl_client example.com=127.0.0.[2,4,6..8]"
will reject clients when the lookup result is 127.0.0.2, 127.0.0.4,
127.0.0.6, 127.0.0.7, or 127.0.0.8.
The setting "postscreen_dnsbl_sites = example.com=127.0.0.[2,4,6..8]"
rejects the same clients.
An IPv4 address pattern has four fields separated by ".". Each
field is either a decimal number, or a sequence inside "[]" that
contains one or more comma-separated decimal numbers or number..number
ranges.
Thus, any pattern field can be a sequence inside "[]", but a "[]"
sequence cannot span multiple address fields, and a pattern field
cannot contain both a number and a "[]" sequence at the same time.
This means that the pattern 1.2.[3.4] is not valid (the sequence
[3.4] cannot span two address fields) and the pattern 1.2.3.3[6..9]
is also not valid (the last field cannot be both number 3 and
sequence [6..9] at the same time).
The syntax for IPv4 patterns is as follows:
v4pattern = v4field "." v4field "." v4field "." v4field
v4field = v4octet | "[" v4sequence "]"
v4octet = any decimal number in the range 0 through 255
v4sequence = v4seq_member | v4sequence "," v4seq_member
v4seq_member = v4octet | v4octet ".." v4octet
Major changes with snapshot 20101105
====================================
The Postfix SMTP server now supports DNS-based whitelisting with
several safety features: permit_dnswl_client whitelists a client
by IP address, and permit_rhswl_client whitelists a client by its
hostname. These features use the same syntax as reject_rbl_client
and reject_rhsbl_client, respectively. The main difference is that
they return PERMIT instead of REJECT.
Whitelisting is primarily a tool to reduce the false positive rate
of DNS blocklist lookups. Client name whitelisting should not be
used to make exceptions to access rules. The reason is that client
name lookup can fail unpredictably due to some temporary outage.
For safety reasons, permit_dnswl_client and permit_rhswl_client are
silently ignored when they would override reject_unauth_destination.
Also for safety reasons, the result is DEFER_IF_REJECT when DNS
whitelist lookup fails (this result will be made configurable).
Incompatibility with snapshot 20101103
======================================
Postfix now requests default delivery status notifications when
adding a recipient with the Milter smfi_addrcpt action, instead of
"never notify" as with Postfix automatically-added recipients
(always_bcc and sender/recipient_bcc_maps).
Incompatibility with snapshot 20101006
======================================
To avoid repeated delivery to mailing lists with pathological nested
alias configurations, the local(8) delivery agent now keeps the
owner-alias attribute of a parent alias, when delivering mail to a
child alias that does not have its own owner alias.
With this change, local addresses from that child alias will be
written to a new queue file, and a temporary error with one local
address will no longer result in repeated delivery to other mailing
list members. Specify "reset_owner_alias = yes" for the older,
more fragile, behavior.
The postconf(5) manpage entry for "reset_owner_alias" has more
background information on this issue.
Incompatibility with snapshot 20100912
======================================
- If your DNSBL queries have a "secret" in the domain name, you
must now censor this information from the postscreen(8) SMTP
replies. For example:
/etc/postfix/main.cf:
postscreen_dnsbl_reply_map = texthash:/etc/postfix/dnsbl_reply
/etc/postfix/dnsbl_reply:
# Secret DNSBL name Name in postscreen(8) replies
secret.zen.spamhaus.org zen.spamhaus.org
The texthash: format is similar to hash: except that there is no need to
run postmap(1) before the file can be used, and that it does not detect
changes after the file is read. It is new with Postfix version 2.8.
- The postscreen "continue" action is now called "ignore". The old
name is still supported but no longer documented.
- The postscreen_hangup_action parameter was removed. Postscreen
now always behaves as if "postscreen_hangup_action = drop".
- The postscreen_cache_retention_time default was increased from
1d to 7d, to avoid deleting results from expensive deep SMTP
protocol tests too quickly.
Major changes with snapshot 20100912
====================================
The main change is a new SMTP protocol engine for deep protocol
tests, and for logging the helo/sender/recipient information when
postscreen rejects an attempt to deliver mail.
CAUTION: when postscreen rejects mail, it replies with the DNSBL
domain name. Use the postscreen_dnsbl_reply_map feature to hide
"password" information in DNSBL domain names. See the poststconf(5)
manpage for a specific example.
Deep protocol tests are implemented by a new SMTP protocol engine
that defers or rejects all attempts to deliver mail. The first,
test detects unauthorized SMTP command pipelining (an SMTP client
sends multiple commands, instead of sending one command and waiting
for the server response); a second deep protocol test implements
the Postfix SMTP server's smtpd_forbidden_commands feature (a client
sends commands such as CONNECT, GET, POST); and a third deep protocol
test detects spambots that send SMTP commands that end in newline
instead of carriage-return/newline. Real spambots rarely make this
mistake, but poorly-written software often does.
Deep protocol tests are disabled by default, because the built-in
SMTP engine cannot not hand off the "live" connection from a good
SMTP client to a Postfix SMTP server process. Instead, postscreen(8)
defers attempts to deliver mail with a 4XX status, and waits for
the client to disconnect. The next time a good client connects,
it will be allowed to talk to a Postfix SMTP server process to
deliver mail.
Incompatibility with snapshot 20100830
======================================
Use "postfix reload" after installing this code, otherwise the
dnsblog(8) daemon may complain. The postscreen-to-dnsblog protocol
had to be changed to support DNSBL query result filters.
Major changes with snapshot 20100830
====================================
Postscreen DNSBL support is extended with optional fixed-string
filters, with optional integral weight factors, and with an adjustable
threshold to block SMTP clients with DNSBL score >= that threshold.
Support for wild-card patterns will be added later.
The updated postscreen configuration syntax is:
postscreen_dnsbl_sites = domain[=ipaddr][*weight] ...
postscreen_dnsbl_threshold = score
Elements inside [] are optional, ipaddr is an IPv4 address, and
weight and score are integral numbers. The [] are not part of the
postscreen_dnsbl_sites input. By default, weight and score are
equal to 1, and entries without filter will match any non-error
DNSBL reply. Use a negative weight value for whitelisting.
Examples:
To use example.com as a high-confidence blocklist, and to block
mail with example.net and example.org only when both agree, use:
postscreen_dnsbl_threshold = 2
postscreen_dnsbl_sites = example.com*2, example.net, example.org
To filter only DNSBL replies containing 127.0.0.4, use:
postscreen_dnsbl_sites = example.com=127.0.0.4
See also postconf(5) for the fine details.
Incompatibility with snapshot 20100827
======================================
The Postfix SMTP client no longer appends the local domain when
looking up a DNS name without ".". Specify "smtp_dns_resolver_options
= res_defnames" to get the old behavior, which may produce unexpected
results.
Incompatibility with snapshot 20100728
======================================
The format of the "postfix/smtpd[pid]: queueid: client=host[addr]"
logfile record has changed. When available, the before-filter client
information and the before-filter queue ID are now appended to the
end of the record.
Major changes with snapshot 20100728
====================================
Improved message tracking across SMTP-based content filters. The
logging example below is from an after-filter SMTP server. Here,
951F692462F is a before-filter queue ID, hades.porcupine.org is a
before-filter SMTP client, while 6B4A9924782 is the after-filter
queue ID, and localhost[127.0.0.1] is the SMTP-based content filter
that sends mail into the after-filter SMTP server.
postfix/smtpd[4074]: 6B4A9924782:
client=localhost[127.0.0.1],
orig_queue_id=951F692462F
orig_client=hades.porcupine.org[168.100.189.10]
Incompatibility with snapshot 20100610
======================================
Postfix no longer appends the system-supplied default CA certificates
to the lists specified with *_tls_CAfile or with *_tls_CApath. This
prevents third-party certificates from getting mail relay permission
with the permit_tls_all_clientcerts feature.
Unfortunately this change may cause compatibility problems when
configurations rely on certificate verification for other purposes.
Specify "tls_append_default_CA = yes" for backwards compatibility.
Incompatibility with snapshot 20100101
======================================
When periodic cache cleanup is enabled (the default), the postscreen(8)
server now requires that the cache database supports the "delete"
and "sequence" operations. To disable periodic cache cleanup specify
a zero postscreen_cache_cleanup_interval value.
Major changes with snapshot 20100101
====================================
Periodic cache cleanup for the postscreen(8) cache database. The
time between cache cleanup runs is controlled with the
postscreen_cache_cleanup_interval (default: 12h) parameter. Cache
cleanup increases the database access latency, so this should not
be run more often than necessary.
In addition, the postscreen_cache_retention_time (default: 1d)
parameter specifies how long to keep an expired entry in the cache.
This prevents a client from being logged as "NEW" after its record
expired only a little while ago.
Incompatibility with snapshot 20091209
======================================
The postscreen daemon now checks the permanent whitelist before
the permanent blacklist. This makes the whitelist easier to use
for its intended purpose, which is to receive mail.
Incompatibility with snapshot 20091008
======================================
NOTE: You must stop and start the Postfix master daemon before you
can use the postscreen(8) daemon. This is needed because the Postfix
"pass" master service type did not work reliably on some systems.
Major changes with snapshot 20091008
====================================
Prototype postscreen(8) server that runs a number of time-consuming
checks in parallel for all incoming SMTP connections, before clients
are allowed to talk to a real Postfix SMTP server. It detects
clients that start talking too soon, or clients that appear on DNS
blocklists, or clients that hang up without sending any command.
By doing these checks in a single postscreen(8) process, Postfix
can avoid wasting one SMTP server process per connection. A side
benefit of postscreen(8)'s DNSBL lookups is that DNS records are
already cached before the Postfix SMTP server looks them up later.
postscreen(8) maintains a temporary whitelist of positive decisions.
Once an SMTP client is whitelisted, it is immediately forwarded
to a real Postfix SMTP server process without further checking.
By default, the program logs only statistics, and it does not run
any checks on clients in mynetworks (primarily, to avoid problems
with buggy SMTP implementations in network appliances). The logging
function alone is already useful for research.
postscreen(8) has been tested on FreeBSD and Linux systems. It
probably needs additional work before it can be used on Solaris.

352
postfix/RELEASE_NOTES-2.8 Normal file
View File

@@ -0,0 +1,352 @@
The stable Postfix release is called postfix-2.8.x where 2=major
release number, 8=minor release number, x=patchlevel. The stable
release never changes except for patches that address bugs or
emergencies. Patches change the patchlevel and the release date.
New features are developed in snapshot releases. These are called
postfix-2.9-yyyymmdd where yyyymmdd is the release date (yyyy=year,
mm=month, dd=day). Patches are never issued for snapshot releases;
instead, a new snapshot is released.
The mail_release_date configuration parameter (format: yyyymmdd)
specifies the release date of a stable release or snapshot release.
If you upgrade from Postfix 2.6 or earlier, read RELEASE_NOTES-2.7
before proceeding.
Major changes - DNSBL/DNSWL support
-----------------------------------
[Feature 20101126] Support for address patterns in DNSBL and DNSWL
lookup results.
For example, "reject_rbl_client example.com=127.0.0.[2,4,6..8]"
will reject clients when the lookup result is 127.0.0.2, 127.0.0.4,
127.0.0.6, 127.0.0.7, or 127.0.0.8.
The setting "postscreen_dnsbl_sites = example.com=127.0.0.[2,4,6..8]"
rejects the same clients.
An IPv4 address pattern has four fields separated by ".". Each
field is either a decimal number, or a sequence inside "[]" that
contains one or more comma-separated decimal numbers or number..number
ranges.
Thus, any pattern field can be a sequence inside "[]", but a "[]"
sequence cannot span multiple address fields, and a pattern field
cannot contain both a number and a "[]" sequence at the same time.
This means that the pattern 1.2.[3.4] is not valid (the sequence
[3.4] cannot span two address fields) and the pattern 1.2.3.3[6..9]
is also not valid (the last field cannot be both number 3 and
sequence [6..9] at the same time).
The syntax for IPv4 patterns is as follows:
v4pattern = v4field "." v4field "." v4field "." v4field
v4field = v4octet | "[" v4sequence "]"
v4octet = any decimal number in the range 0 through 255
v4sequence = v4seq_member | v4sequence "," v4seq_member
v4seq_member = v4octet | v4octet ".." v4octet
[Feature 20101105] The Postfix SMTP server now supports DNS-based
whitelisting with several safety features: permit_dnswl_client
whitelists a client by IP address, and permit_rhswl_client whitelists
a client by its hostname. These features use the same syntax as
reject_rbl_client and reject_rhsbl_client, respectively. The main
difference is that they return PERMIT instead of REJECT.
Whitelisting is primarily a tool to reduce the false positive rate
of DNS blocklist lookups. Client name whitelisting should not be
used to make exceptions to access rules. The reason is that client
name lookup can fail unpredictably due to some temporary outage.
For safety reasons, permit_dnswl_client and permit_rhswl_client are
silently ignored when they would override reject_unauth_destination.
Also for safety reasons, the result is DEFER_IF_REJECT when DNS
whitelist lookup fails (this result will be made configurable).
Major changes - Milter suppport
-------------------------------
[Incompat 20101103] Postfix now requests default delivery status
notifications when adding a recipient with the Milter smfi_addrcpt
action, instead of "never notify" as with Postfix automatically-added
recipients (always_bcc and sender/recipient_bcc_maps).
Major changes - alias expansion
-------------------------------
[Incompat 20101202] Postfix now reports a temporary delivery error
when the result of virtual alias expansion would exceed the
virtual_alias_recursion_limit or virtual_alias_expansion_limit.
Previously, Postfix would silently drop the excess recipients and
deliver the message.
[Incompat 20101006] To avoid repeated delivery to mailing lists
with pathological nested alias configurations, the local(8) delivery
agent now keeps the owner-alias attribute of a parent alias, when
delivering mail to a child alias that does not have its own owner
alias.
With this change, local addresses from that child alias will be
written to a new queue file, and a temporary error with one local
address will no longer result in repeated delivery to other mailing
list members. Specify "reset_owner_alias = yes" for the older,
more fragile, behavior.
The postconf(5) manpage entry for "reset_owner_alias" has more
background information on this issue.
Major changes - dns lookup
--------------------------
[Incompat 20100827] The Postfix SMTP client no longer appends the
local domain when looking up a DNS name without ".". Specify
"smtp_dns_resolver_options = res_defnames" to get the old behavior,
which may produce unexpected results.
Major changes - logging
-----------------------
[Incompat 20100728] The format of the "postfix/smtpd[pid]: queueid:
client=host[addr]" logfile record has changed. When available, the
before-filter client information and the before-filter queue ID are
now appended to the end of the record.
[Feature 20100728] Improved message tracking across SMTP-based
content filters. The logging example below is from an after-filter
SMTP server. Here, 951F692462F is a before-filter queue ID,
hades.porcupine.org is a before-filter SMTP client, while 6B4A9924782
is the after-filter queue ID, and localhost[127.0.0.1] is the
SMTP-based content filter that sends mail into the after-filter
SMTP server.
postfix/smtpd[4074]: 6B4A9924782:
client=localhost[127.0.0.1],
orig_queue_id=951F692462F
orig_client=hades.porcupine.org[168.100.189.10]
Major changes - reply footer
----------------------------
[Feature 20110105] The SMTP server now supports contact information
that is appended to "reject" responses. This includes SMTP server
responses that aren't logged to the maillog file, such as responses
to syntax errors, or unsupported commands.
Example:
smtpd_reject_footer = For assistance, call 800-555-0101.
Server response:
550-5.5.1 <user@example> Recipient address rejected: User unknown
550 5.5.1 For assistance, call 800-555-0101.
This feature supports macro expansion ($client_address, $localtime,
etc.), as documented in the postconf(5) manpage.
This feature is also supported as postscreen_reject_footer using
the same setting as smtpd_reject_footer by default.
Major changes - rfc compliance
------------------------------
[Incompat 20101206] Postfix by default no longer adds a "To:
undisclosed-recipients:;" header when no recipient specified in the
message header. The Internet mail RFCs have supported messages
without recipient header for almost 10 years now.
For backwards compatibility, specify:
/etc/postfix/main.cf
undisclosed_recipients_header = To: undisclosed-recipients:;
Note: both the ":" and ";" are required.
Major changes - tls support
---------------------------
[Incompat 20110102] The Postfix SMTP server now always re-computes
the SASL mechanism list after successful completion of the STARTTLS
command. Earlier versions only re-computed the mechanism list when
the values of smtp_sasl_tls_security_options and smtp_sasl_security_options
differ. This could produce incorrect results, because the Dovecot
authentication server may change responses when the SMTP session
is encrypted.
[Incompat 20110102] The smtpd_starttls_timeout default value is now
stress-dependent. By default, TLS negotiations must now complete
under overload in 10s instead of 300s.
[Feature 20101223] The new tls_disable_workarounds parameter specifies
a list or bit-mask of OpenSSL bug work-arounds to disable. This may
be necessary if one of the work-arounds enabled by default in OpenSSL
proves to pose a security risk, or introduces an unexpected
interoperability issue. Some bug work-arounds known to be problematic
are disabled in the default value of the parameter when linked with
an OpenSSL library that could be vulnerable. See postconf(5) and
TLS_README for details.
With "tls_preempt_cipherlist = yes" the Postfix SMTP server will
choose its most preferred cipher that is supported (offered) by the
client. This can lead to a more secure or performant cipher choice,
but may also introduce interoperability problems when a client
announces support for a cipher that does not work. See postconf(5)
and TLS_README for details.
[Feature 20101217] The lower-level code in the TLS engine was
simplified by removing an unnecessary layer of data copying. OpenSSL
now writes directly to the network. The difference in performance
should be hardly noticeable.
[Incompat 20100610] Postfix no longer appends the system-supplied
default CA certificates to the lists specified with *_tls_CAfile
or with *_tls_CApath. This prevents third-party certificates from
getting mail relay permission with the permit_tls_all_clientcerts
feature.
Unfortunately this change may cause compatibility problems when
configurations rely on certificate verification for other purposes.
Specify "tls_append_default_CA = yes" for backwards compatibility.
Major changes - postscreen
--------------------------
[Incompat 20110111] The postscreen_access_list feature replaces the
postscreen_whitelist_networks and postscreen_blacklist_networks
features. Reason: CIDR-style access maps are some 100x faster than
the code that implemented the postscreen_white/blacklist_networks
support. CIDR maps can match about 100 million CIDR patterns/second
on a modern CPU, which is not blindingly fast but adequate for the
near future.
[Feature 20110102] STARTTLS support for the postscreen(8) daemon.
This is implemented by a new tlsproxy(8) daemon that you will need
to enable in master.cf (see POSTSCREEN_README for instructions).
tlsproxy(8) implements its own tlsproxy_mumble versions of TLS-related
smtpd_mumble parameters. This leaves no confusion about which
parameters will affect tlsproxy(8) behavior, but it adds another
25 parameters to the documentation.
[Incompat 20100912] If your DNSBL queries have a "secret" in the
domain name, you must now censor this information from the postscreen(8)
SMTP replies. For example:
/etc/postfix/main.cf:
postscreen_dnsbl_reply_map = texthash:/etc/postfix/dnsbl_reply
/etc/postfix/dnsbl_reply:
# Secret DNSBL name Name in postscreen(8) replies
secret.zen.spamhaus.org zen.spamhaus.org
The texthash: format is similar to hash: except that there is no need to
run postmap(1) before the file can be used, and that it does not detect
changes after the file is read. It is new with Postfix version 2.8.
[Incompat 20100912] The postscreen "continue" action is now called
"ignore". The old name is still supported but no longer documented.
[Incompat 20100912] The postscreen_hangup_action parameter was
removed. Postscreen now always behaves as if "postscreen_hangup_action
= drop".
[Incompat 20100912] The postscreen_cache_retention_time default was
increased from 1d to 7d, to avoid deleting results from expensive
deep SMTP protocol tests too quickly.
[Feature 20100912] SMTP protocol engine for deep protocol tests,
and for logging the helo/sender/recipient information when postscreen
rejects an attempt to deliver mail.
The postscreen SMTP protocol engine implements a number of deep
protocol tests and defers or rejects all attempts to deliver mail.
The first test detects unauthorized SMTP command pipelining (an
SMTP client sends multiple commands, instead of sending one command
and waiting for the server response); a second deep protocol test
implements the Postfix SMTP server's smtpd_forbidden_commands feature
(a client sends commands such as CONNECT, GET, POST); and a third
deep protocol test detects spambots that send SMTP commands that
end in newline instead of carriage-return/newline. Real spambots
rarely make this mistake, but poorly-written software often does.
Deep protocol tests are disabled by default, because the built-in
SMTP engine cannot not hand off the "live" connection from a good
SMTP client to a Postfix SMTP server process. To work around this,
postscreen(8) defers attempts to deliver mail with a 4XX status,
and waits for the client to disconnect. The next time a good client
connects, it will be allowed to talk to a Postfix SMTP server process
to deliver mail.
[Feature 20100830] Postscreen DNSBL support is extended with optional
fixed-string filters, with optional integral weight factors, and
with an adjustable threshold to block SMTP clients with DNSBL score
>= that threshold. Reply filters will be implemented later.
The updated postscreen configuration syntax is:
postscreen_dnsbl_sites = domain[=ipaddr][*weight] ...
postscreen_dnsbl_threshold = score
Elements inside [] are optional, ipaddr is an IPv4 address, and
weight and score are integral numbers. The [] are not part of the
postscreen_dnsbl_sites input. By default, weight and score are
equal to 1, and entries without filter will match any non-error
DNSBL reply. Use a negative weight value for whitelisting.
Examples:
To use example.com as a high-confidence blocklist, and to block
mail with example.net and example.org only when both agree, use:
postscreen_dnsbl_threshold = 2
postscreen_dnsbl_sites = example.com*2, example.net, example.org
To filter only DNSBL replies containing 127.0.0.4, use:
postscreen_dnsbl_sites = example.com=127.0.0.4
See also postconf(5) for the fine details.
[Incompat 20100101] When periodic cache cleanup is enabled (the
default), the postscreen(8) server now requires that the cache
database supports the "delete" and "sequence" operations. To disable
periodic cache cleanup specify a zero postscreen_cache_cleanup_interval
value.
[Feature 20100101] Periodic cache cleanup for the postscreen(8)
cache database. The time between cache cleanup runs is controlled
with the postscreen_cache_cleanup_interval (default: 12h) parameter.
Cache cleanup increases the database access latency, so this should
not be run more often than necessary.
In addition, the postscreen_cache_retention_time (default: 1d)
parameter specifies how long to keep an expired entry in the cache.
This prevents a client from being logged as "NEW" after its record
expired only a little while ago.
[Incompat 20091008] If you upgrade from Postfix 2.6 or earlier, you
must stop and start the Postfix master daemon before you can use
the postscreen(8) daemon. This is needed because the Postfix 2.6
"pass" master service type did not work reliably on some systems.
[Feature 20091008] Prototype postscreen(8) server that runs a number
of time-consuming checks in parallel for all incoming SMTP connections,
before clients are allowed to talk to a real Postfix SMTP server.
It detects clients that start talking too soon, or clients that
appear on DNS blocklists, or clients that hang up without sending
any command.
By doing these checks in a single postscreen(8) process, Postfix
can avoid wasting one SMTP server process per connection. A side
benefit of postscreen(8)'s DNSBL lookups is that DNS records are
already cached before the Postfix SMTP server looks them up later.
postscreen(8) maintains a temporary whitelist of positive decisions.
Once an SMTP client is whitelisted, it is immediately forwarded to
a real Postfix SMTP server process without further checking.
By default, the program logs only statistics, and it does not run
any checks on clients in mynetworks (primarily, to avoid problems
with buggy SMTP implementations in network appliances). The logging
function alone is already useful for research.

56
postfix/html/POSTSCREEN_README.html
View File

@@ -28,18 +28,18 @@ mail from end-user clients (MUAs). In a typical deployment,
<a href="postscreen.8.html">postscreen(8)</a> is used on the "port 25" service, while MUA clients <a href="postscreen.8.html">postscreen(8)</a> is used on the "port 25" service, while MUA clients
submit mail via the submission service. </p> submit mail via the submission service. </p>
<p> <a href="postscreen.8.html">postscreen(8)</a> is the first layer in a multi-layer defense. <p> <p> <a href="postscreen.8.html">postscreen(8)</a> is part of a multi-layer defense. <p>
<ul> <ul>
<li> <p> The <a href="postscreen.8.html">postscreen(8)</a> layer blocks connections from zombies <li> <p> As the first layer, <a href="postscreen.8.html">postscreen(8)</a> blocks connections from
and other spambots that are responsible for about 90% of all spam. zombies and other spambots that are responsible for about 90% of
It is implemented as a single process to make this defense as cheap all spam. It is implemented as a single process to make this defense
as possible. </p> as cheap as possible. </p>
<li> <p> The second layer implements more complex SMTP-level access <li> <p> The second layer implements more complex SMTP-level access
checks that are available with Postfix SMTP servers, policy daemons, checks with Postfix SMTP servers, policy daemons, and Milter
and Milter applications. </p> applications. </p>
<li> <p> The third layer performs light-weight content inspection <li> <p> The third layer performs light-weight content inspection
with the Postfix built-in <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>. This can with the Postfix built-in <a href="postconf.5.html#header_checks">header_checks</a> and <a href="postconf.5.html#body_checks">body_checks</a>. This can
@@ -672,6 +672,23 @@ without blocking mail: </p>
<ol> <ol>
<li> <p> Make sure that local clients and systems with non-standard
SMTP implementations are excluded from any <a href="postscreen.8.html">postscreen(8)</a> tests. The
default is to exclude all clients in <a href="postconf.5.html#mynetworks">mynetworks</a>. To exclude additional
clients, for example, third-party performance monitoring tools (these
tend to have broken SMTP implementations): </p>
<pre>
/etc/postfix/<a href="postconf.5.html">main.cf</a>:
# Exclude broken clients by whitelisting. Clients in <a href="postconf.5.html#mynetworks">mynetworks</a>
# should always be whitelisted.
<a href="postconf.5.html#postscreen_access_list">postscreen_access_list</a> = <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>,
<a href="cidr_table.5.html">cidr</a>:/etc/postfix/postscreen_access.cidr
/etc/postfix/postscreen_access.<a href="cidr_table.5.html">cidr</a>:
192.168.254.0/24 permit
</pre>
<li> <p> Comment out the "<tt>smtp inet ... smtpd</tt>" service <li> <p> Comment out the "<tt>smtp inet ... smtpd</tt>" service
in <a href="master.5.html">master.cf</a>, including any "<tt>-o parameter=value</tt>" entries in <a href="master.5.html">master.cf</a>, including any "<tt>-o parameter=value</tt>" entries
that follow. </p> that follow. </p>
@@ -768,10 +785,6 @@ string. </p>
greeting</a>" for details about the logging from these postscreen(8) greeting</a>" for details about the logging from these postscreen(8)
tests. </p> tests. </p>
<li> <p> By default, <a href="postscreen.8.html">postscreen(8)</a> whitelists all clients in
<a href="postconf.5.html#mynetworks">mynetworks</a>. This is a safety feature to avoid you from getting
into trouble with local users. </p>
<li> <p> If you run Postfix 2.6 or earlier you must stop and start <li> <p> If you run Postfix 2.6 or earlier you must stop and start
the master daemon ("<tt>postfix stop; postfix start</tt>"). This the master daemon ("<tt>postfix stop; postfix start</tt>"). This
is needed because the Postfix "pass" master service type did not is needed because the Postfix "pass" master service type did not
@@ -802,6 +815,27 @@ services. </p>
<h3> <a name="blocking"> Blocking mail with postscreen(8) </a> </h3> <h3> <a name="blocking"> Blocking mail with postscreen(8) </a> </h3>
<p> For compatibility with <a href="smtpd.8.html">smtpd(8)</a>, <a href="postscreen.8.html">postscreen(8)</a> implements the
<a href="postconf.5.html#soft_bounce">soft_bounce</a> safety feature. This causes Postfix to reject mail with
a "try again" reply code. </p>
<ul>
<li> <p> To turn this on for all of Postfix, specify "<tt><a href="postconf.5.html#soft_bounce">soft_bounce</a>
= yes</tt>" in <a href="postconf.5.html">main.cf</a>. </p>
<li> <p> To turn this on for <a href="postscreen.8.html">postscreen(8)</a> only, append "<tt>-o
<a href="postconf.5.html#soft_bounce">soft_bounce</a>=yes</tt>" (note: NO SPACES around '=') to the postscreen
entry in <a href="master.5.html">master.cf</a>. <p>
</ul>
<p> Execute "<tt>postfix reload</tt>" to make the change effective. </p>
<p> After testing, do not forget to remove the <a href="postconf.5.html#soft_bounce">soft_bounce</a> feature,
otherwise senders won't receive their non-delivery notification
until many days later. </p>
<p> To use the <a href="postscreen.8.html">postscreen(8)</a> service to block mail, edit <a href="postconf.5.html">main.cf</a> and <p> To use the <a href="postscreen.8.html">postscreen(8)</a> service to block mail, edit <a href="postconf.5.html">main.cf</a> and
specify one or more of: </p> specify one or more of: </p>

5
postfix/html/dnsblog.8.html
View File

@@ -14,10 +14,11 @@ DNSBLOG(8) DNSBLOG(8)
<b>DESCRIPTION</b> <b>DESCRIPTION</b>
The <a href="dnsblog.8.html"><b>dnsblog</b>(8)</a> server implements an ad-hoc DNS The <a href="dnsblog.8.html"><b>dnsblog</b>(8)</a> server implements an ad-hoc DNS
white/blacklist lookup service that will eventually be white/blacklist lookup service. This may eventually be
replaced by an UDP client that is built directly into the replaced by an UDP client that is built directly into the
<a href="postscreen.8.html"><b>postscreen</b>(8)</a> server. <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server.
<b>PROTOCOL</b>
With each connection, the <a href="dnsblog.8.html"><b>dnsblog</b>(8)</a> server receives a DNS With each connection, the <a href="dnsblog.8.html"><b>dnsblog</b>(8)</a> server receives a DNS
white/blacklist domain name and an IP address. If the white/blacklist domain name and an IP address. If the
address is listed under the DNS white/blacklist, the <b>dns-</b> address is listed under the DNS white/blacklist, the <b>dns-</b>
@@ -84,7 +85,7 @@ DNSBLOG(8) DNSBLOG(8)
software. software.
<b>HISTORY</b> <b>HISTORY</b>
This service is temporary with Postfix version 2.7. This service was introduced with Postfix version 2.8.
<b>AUTHOR(S)</b> <b>AUTHOR(S)</b>
Wietse Venema Wietse Venema

21
postfix/html/postconf.5.html
View File

@@ -6634,7 +6634,7 @@ and enabled instances are processed in reverse order. </p>
<DT><b><a name="postscreen_access_list">postscreen_access_list</a> <DT><b><a name="postscreen_access_list">postscreen_access_list</a>
(default: <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>)</b></DT><DD> (default: <a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>)</b></DT><DD>
<p> Permanent white/blacklist for remote SMTP client IP addresses; <p> Permanent white/blacklist for remote SMTP client IP addresses.
<a href="postscreen.8.html">postscreen(8)</a> searches this list immediately after a remote SMTP <a href="postscreen.8.html">postscreen(8)</a> searches this list immediately after a remote SMTP
client connects. Specify a comma- or whitespace-separated list of client connects. Specify a comma- or whitespace-separated list of
commands (in upper or lower case) or lookup tables. The search stops commands (in upper or lower case) or lookup tables. The search stops
@@ -6664,10 +6664,12 @@ server process. </dd>
the search. Subject the client to the action configured with the the search. Subject the client to the action configured with the
<a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> configuration parameter. </dd> <a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> configuration parameter. </dd>
<dt> <b> dunno </b> </dt> <dd> When used inside a lookup table, <dt> <b> dunno </b> </dt> <dd> All <a href="postscreen.8.html">postscreen(8)</a> access lists
return from the lookup table and evaluate the next command. <br> implicitly have this command at the end. <br> When <b> dunno </b>
When used outside a lookup table, terminate the search, and subject is executed inside a lookup table, return from the lookup table and
the client to the configured before/after 220 greeting tests. </dd> evaluate the next command. <br> When <b> dunno </b> is executed
outside a lookup table, terminate the search, and subject the client
to the configured before/after 220 greeting tests. </dd>
</dl> </dl>
@@ -6762,8 +6764,8 @@ one-letter suffix that specifies the time unit). Time units: s
(default: ignore)</b></DT><DD> (default: ignore)</b></DT><DD>
<p> The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client is <p> The action that <a href="postscreen.8.html">postscreen(8)</a> takes when an SMTP client is
permanently blacklisted with the <a href="postconf.5.html#postscreen_blacklist_networks">postscreen_blacklist_networks</a> permanently blacklisted with the <a href="postconf.5.html#postscreen_access_list">postscreen_access_list</a> parameter.
parameter. Specify one of the following: </p> Specify one of the following: </p>
<dl> <dl>
@@ -6885,9 +6887,8 @@ See <a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a> for
<DT><b><a name="postscreen_command_time_limit">postscreen_command_time_limit</a> <DT><b><a name="postscreen_command_time_limit">postscreen_command_time_limit</a>
(default: ${stress?10}${stress:300}s)</b></DT><DD> (default: ${stress?10}${stress:300}s)</b></DT><DD>
<p> The command "read" time limit for <a href="postscreen.8.html">postscreen(8)</a>'s built-in SMTP <p> The time limit to read an entire command line with <a href="postscreen.8.html">postscreen(8)</a>'s
protocol engine. This bounds the time to receive an entire command. built-in SMTP protocol engine. </p>
</p>
<p> This feature is available in Postfix 2.8. </p> <p> This feature is available in Postfix 2.8. </p>

217
postfix/html/postscreen.8.html
View File

@@ -71,84 +71,100 @@ POSTSCREEN(8) POSTSCREEN(8)
Problems and transactions are logged to <b>syslogd</b>(8). Problems and transactions are logged to <b>syslogd</b>(8).
<b>BUGS</b> <b>BUGS</b>
The <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server does not yet implement the The <a href="postscreen.8.html"><b>postscreen</b>(8)</a> built-in SMTP protocol engine currently
<b><a href="postconf.5.html#soft_bounce">soft_bounce</a></b> feature. does not announce support for AUTH, XCLIENT or XFORWARD.
Support for AUTH may be added in the future. In the mean
The <a href="postscreen.8.html"><b>postscreen</b>(8)</a> built-in SMTP protocol engine currently
does not announce support for AUTH, XCLIENT or XFORWARD.
Support for AUTH may be added in the future. In the mean
time, if you need to make these services available on port time, if you need to make these services available on port
25, then do not enable the optional "after 220 server 25, then do not enable the optional "after 220 server
greeting" tests. greeting" tests.
The optional "after 220 server greeting" tests involve The optional "after 220 server greeting" tests involve
<a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP protocol engine. When these <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP protocol engine. When these
tests succeed, <a href="postscreen.8.html"><b>postscreen</b>(8)</a> adds the client to the tempo- tests succeed, <a href="postscreen.8.html"><b>postscreen</b>(8)</a> adds the client to the tempo-
rary whitelist but it cannot not hand off the "live" con- rary whitelist but it cannot not hand off the "live" con-
nection to a Postfix SMTP server process in the middle of nection to a Postfix SMTP server process in the middle of
a session. Instead, <a href="postscreen.8.html"><b>postscreen</b>(8)</a> defers attempts to a session. Instead, <a href="postscreen.8.html"><b>postscreen</b>(8)</a> defers attempts to
deliver mail with a 4XX status, and waits for the client deliver mail with a 4XX status, and waits for the client
to disconnect. The next time a good client connects, it to disconnect. The next time a good client connects, it
will be allowed to talk to a Postfix SMTP server process will be allowed to talk to a Postfix SMTP server process
to deliver mail. <a href="postscreen.8.html"><b>postscreen</b>(8)</a> mitigates the impact of to deliver mail. <a href="postscreen.8.html"><b>postscreen</b>(8)</a> mitigates the impact of
this limitation by giving such tests a long expiration this limitation by giving such tests a long expiration
time. time.
<b>CONFIGURATION PARAMETERS</b> <b>CONFIGURATION PARAMETERS</b>
Changes to <a href="postconf.5.html">main.cf</a> are not picked up automatically, as Changes to <a href="postconf.5.html">main.cf</a> are not picked up automatically, as
<a href="postscreen.8.html"><b>postscreen</b>(8)</a> processes may run for several hours. Use <a href="postscreen.8.html"><b>postscreen</b>(8)</a> processes may run for several hours. Use
the command "postfix reload" after a configuration change. the command "postfix reload" after a configuration change.
The text below provides only a parameter summary. See The text below provides only a parameter summary. See
<a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples. <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples.
NOTE: Some <a href="postscreen.8.html"><b>postscreen</b>(8)</a> parameters implement stress- NOTE: Some <a href="postscreen.8.html"><b>postscreen</b>(8)</a> parameters implement stress-
dependent behavior. This is supported only when the dependent behavior. This is supported only when the
default parameter value is stress-dependent (that is, it default parameter value is stress-dependent (that is, it
looks like ${stress?X}${stress:Y}, or it is the $<i>name</i> of looks like ${stress?X}${stress:Y}, or it is the $<i>name</i> of
an smtpd parameter with a stress-dependent default). an smtpd parameter with a stress-dependent default).
Other parameters always evaluate as if the <b>stress</b> parame- Other parameters always evaluate as if the <b>stress</b> parame-
ter value is the empty string. ter value is the empty string.
<b>COMPATIBILITY CONTROLS</b> <b>COMPATIBILITY CONTROLS</b>
<b><a href="postconf.5.html#postscreen_command_filter">postscreen_command_filter</a> ($<a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a>)</b> <b><a href="postconf.5.html#postscreen_command_filter">postscreen_command_filter</a> ($<a href="postconf.5.html#smtpd_command_filter">smtpd_command_filter</a>)</b>
A mechanism to transform commands from remote SMTP A mechanism to transform commands from remote SMTP
clients. clients.
<b><a href="postconf.5.html#postscreen_discard_ehlo_keyword_address_maps">postscreen_discard_ehlo_keyword_address_maps</a> ($<a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">smtpd_dis</a>-</b> <b><a href="postconf.5.html#postscreen_discard_ehlo_keyword_address_maps">postscreen_discard_ehlo_keyword_address_maps</a> ($<a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">smtpd_dis</a>-</b>
<b><a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">card_ehlo_keyword_address_maps</a>)</b> <b><a href="postconf.5.html#smtpd_discard_ehlo_keyword_address_maps">card_ehlo_keyword_address_maps</a>)</b>
Lookup tables, indexed by the remote SMTP client Lookup tables, indexed by the remote SMTP client
address, with case insensitive lists of EHLO key- address, with case insensitive lists of EHLO key-
words (pipelining, starttls, auth, etc.) that the words (pipelining, starttls, auth, etc.) that the
<a href="postscreen.8.html"><b>postscreen</b>(8)</a> server will not send in the EHLO <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server will not send in the EHLO
response to a remote SMTP client. response to a remote SMTP client.
<b><a href="postconf.5.html#postscreen_discard_ehlo_keywords">postscreen_discard_ehlo_keywords</a> ($<a href="postconf.5.html#smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_key</a>-</b> <b><a href="postconf.5.html#postscreen_discard_ehlo_keywords">postscreen_discard_ehlo_keywords</a> ($<a href="postconf.5.html#smtpd_discard_ehlo_keywords">smtpd_discard_ehlo_key</a>-</b>
<b><a href="postconf.5.html#smtpd_discard_ehlo_keywords">words</a>)</b> <b><a href="postconf.5.html#smtpd_discard_ehlo_keywords">words</a>)</b>
A case insensitive list of EHLO keywords (pipelin- A case insensitive list of EHLO keywords (pipelin-
ing, starttls, auth, etc.) that the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> ing, starttls, auth, etc.) that the <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
server will not send in the EHLO response to a server will not send in the EHLO response to a
remote SMTP client. remote SMTP client.
<b>BEFORE-GREETING TRIAGE</b> <b>TROUBLE SHOOTING CONTROLS</b>
<b><a href="postconf.5.html#dnsblog_service_name">dnsblog_service_name</a> (dnsblog)</b> <b><a href="postconf.5.html#postscreen_expansion_filter">postscreen_expansion_filter</a> (see 'postconf -d' output)</b>
The name of the <a href="dnsblog.8.html"><b>dnsblog</b>(8)</a> service entry in mas- List of characters that are permitted in
ter.cf. <a href="postconf.5.html#postscreen_reject_footer">postscreen_reject_footer</a> attribute expansions.
<b><a href="postconf.5.html#postscreen_reject_footer">postscreen_reject_footer</a> ($<a href="postconf.5.html#smtpd_reject_footer">smtpd_reject_footer</a>)</b>
Optional information that is appended after a 4XX
or 5XX server 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 to the sender.
<b>PERMANENT WHITE/BLACKLIST TEST</b>
This test is executed immediately after a remote SMTP
client connects. If a client is permanently whitelisted,
the client will be handed off immediately to a Postfix
SMTP server process.
<b><a href="postconf.5.html#postscreen_access_list">postscreen_access_list</a> (<a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>)</b> <b><a href="postconf.5.html#postscreen_access_list">postscreen_access_list</a> (<a href="postconf.5.html#permit_mynetworks">permit_mynetworks</a>)</b>
Permanent white/blacklist for remote SMTP client IP Permanent white/blacklist for remote SMTP client IP
addresses; <a href="postscreen.8.html"><b>postscreen</b>(8)</a> searches this list immedi- addresses.
ately after a remote SMTP client connects.
<b><a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> (ignore)</b> <b><a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> (ignore)</b>
The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
client is permanently blacklisted with the client is permanently blacklisted with the
<a href="postconf.5.html#postscreen_blacklist_networks">postscreen_blacklist_networks</a> parameter. <a href="postconf.5.html#postscreen_access_list">postscreen_access_list</a> parameter.
<b><a href="postconf.5.html#postscreen_blacklist_networks">postscreen_blacklist_networks</a> (empty)</b> <b>BEFORE-GREETING TESTS</b>
Network addresses that are permanently blacklisted; These tests are executed before the remote SMTP client
see the <a href="postconf.5.html#postscreen_blacklist_action">postscreen_blacklist_action</a> parameter for receives the "220 servername" greeting. If no tests remain
possible actions. after the successful completion of this phase, the client
will be handed off immediately to a Postfix SMTP server
process.
<b><a href="postconf.5.html#dnsblog_service_name">dnsblog_service_name</a> (dnsblog)</b>
The name of the <a href="dnsblog.8.html"><b>dnsblog</b>(8)</a> service entry in mas-
ter.cf.
<b><a href="postconf.5.html#postscreen_dnsbl_action">postscreen_dnsbl_action</a> (ignore)</b> <b><a href="postconf.5.html#postscreen_dnsbl_action">postscreen_dnsbl_action</a> (ignore)</b>
The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
@@ -191,7 +207,18 @@ POSTSCREEN(8) POSTSCREEN(8)
(default: up to 2 seconds under stress, up to 6 (default: up to 2 seconds under stress, up to 6
seconds otherwise). seconds otherwise).
<b>AFTER-GREETING TRIAGE</b> <b><a href="postconf.5.html#smtpd_service_name">smtpd_service_name</a> (smtpd)</b>
The internal service that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> forwards
allowed connections to.
<b>AFTER-GREETING TESTS</b>
These tests are executed after the remote SMTP client
receives the "220 servername" greeting. If a client passes
all tests during this phase, it will receive a 4XX
response to RCPT TO commands until the client hangs up.
After this, the client will be allowed to talk directly to
a Postfix SMTP server process.
<b><a href="postconf.5.html#postscreen_bare_newline_action">postscreen_bare_newline_action</a> (ignore)</b> <b><a href="postconf.5.html#postscreen_bare_newline_action">postscreen_bare_newline_action</a> (ignore)</b>
The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP The action that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> takes when an SMTP
client sends a bare newline character, that is, a client sends a bare newline character, that is, a
@@ -231,150 +258,136 @@ POSTSCREEN(8) POSTSCREEN(8)
Enable "pipelining" SMTP protocol tests in the Enable "pipelining" SMTP protocol tests in the
<a href="postscreen.8.html"><b>postscreen</b>(8)</a> server. <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server.
<b>AFTER-TRIAGE CONTROLS</b>
<b><a href="postconf.5.html#smtpd_service_name">smtpd_service_name</a> (smtpd)</b>
The internal service that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> forwards
allowed connections to.
<b>CACHE CONTROLS</b> <b>CACHE CONTROLS</b>
<b><a href="postconf.5.html#postscreen_cache_cleanup_interval">postscreen_cache_cleanup_interval</a> (12h)</b> <b><a href="postconf.5.html#postscreen_cache_cleanup_interval">postscreen_cache_cleanup_interval</a> (12h)</b>
The amount of time between <a href="postscreen.8.html"><b>postscreen</b>(8)</a> cache The amount of time between <a href="postscreen.8.html"><b>postscreen</b>(8)</a> cache
cleanup runs. cleanup runs.
<b><a href="postconf.5.html#postscreen_cache_map">postscreen_cache_map</a> (btree:$data_direc-</b> <b><a href="postconf.5.html#postscreen_cache_map">postscreen_cache_map</a> (btree:$data_direc-</b>
<b>tory/postscreen_cache)</b> <b>tory/postscreen_cache)</b>
Persistent storage for the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server Persistent storage for the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> server
decisions. decisions.
<b><a href="postconf.5.html#postscreen_cache_retention_time">postscreen_cache_retention_time</a> (7d)</b> <b><a href="postconf.5.html#postscreen_cache_retention_time">postscreen_cache_retention_time</a> (7d)</b>
The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache an The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will cache an
expired temporary whitelist entry before it is expired temporary whitelist entry before it is
removed. removed.
<b><a href="postconf.5.html#postscreen_bare_newline_ttl">postscreen_bare_newline_ttl</a> (30d)</b> <b><a href="postconf.5.html#postscreen_bare_newline_ttl">postscreen_bare_newline_ttl</a> (30d)</b>
The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the
result from a successful "bare newline" SMTP proto- result from a successful "bare newline" SMTP proto-
col test. col test.
<b><a href="postconf.5.html#postscreen_dnsbl_ttl">postscreen_dnsbl_ttl</a> (1h)</b> <b><a href="postconf.5.html#postscreen_dnsbl_ttl">postscreen_dnsbl_ttl</a> (1h)</b>
The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the
result from a successful DNS blocklist test. result from a successful DNS blocklist test.
<b><a href="postconf.5.html#postscreen_greet_ttl">postscreen_greet_ttl</a> (1d)</b> <b><a href="postconf.5.html#postscreen_greet_ttl">postscreen_greet_ttl</a> (1d)</b>
The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the
result from a successful PREGREET test. result from a successful PREGREET test.
<b><a href="postconf.5.html#postscreen_non_smtp_command_ttl">postscreen_non_smtp_command_ttl</a> (30d)</b> <b><a href="postconf.5.html#postscreen_non_smtp_command_ttl">postscreen_non_smtp_command_ttl</a> (30d)</b>
The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the
result from a successful "non_smtp_command" SMTP result from a successful "non_smtp_command" SMTP
protocol test. protocol test.
<b><a href="postconf.5.html#postscreen_pipelining_ttl">postscreen_pipelining_ttl</a> (30d)</b> <b><a href="postconf.5.html#postscreen_pipelining_ttl">postscreen_pipelining_ttl</a> (30d)</b>
The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the The amount of time that <a href="postscreen.8.html"><b>postscreen</b>(8)</a> will use the
result from a successful "pipelining" SMTP protocol result from a successful "pipelining" SMTP protocol
test. test.
<b>RESOURCE CONTROLS</b> <b>RESOURCE CONTROLS</b>
<b><a href="postconf.5.html#line_length_limit">line_length_limit</a> (2048)</b> <b><a href="postconf.5.html#line_length_limit">line_length_limit</a> (2048)</b>
Upon input, long lines are chopped up into pieces Upon input, long lines are chopped up into pieces
of at most this length; upon delivery, long lines of at most this length; upon delivery, long lines
are reconstructed. are reconstructed.
<b><a href="postconf.5.html#postscreen_client_connection_count_limit">postscreen_client_connection_count_limit</a></b> <b><a href="postconf.5.html#postscreen_client_connection_count_limit">postscreen_client_connection_count_limit</a></b>
<b>($<a href="postconf.5.html#smtpd_client_connection_count_limit">smtpd_client_connection_count_limit</a>)</b> <b>($<a href="postconf.5.html#smtpd_client_connection_count_limit">smtpd_client_connection_count_limit</a>)</b>
How many simultaneous connections any client is How many simultaneous connections any client is
allowed to have with the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> daemon. allowed to have with the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> daemon.
<b><a href="postconf.5.html#postscreen_command_count_limit">postscreen_command_count_limit</a> (20)</b> <b><a href="postconf.5.html#postscreen_command_count_limit">postscreen_command_count_limit</a> (20)</b>
The limit on the total number of commands per SMTP The limit on the total number of commands per SMTP
session for <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP protocol session for <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP protocol
engine. engine.
<b><a href="postconf.5.html#postscreen_command_time_limit">postscreen_command_time_limit</a> (${stress?10}${stress:300}s)</b> <b><a href="postconf.5.html#postscreen_command_time_limit">postscreen_command_time_limit</a> (${stress?10}${stress:300}s)</b>
The command "read" time limit for <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s The time limit to read an entire command line with
built-in SMTP protocol engine. <a href="postscreen.8.html"><b>postscreen</b>(8)</a>'s built-in SMTP protocol engine.
<b><a href="postconf.5.html#postscreen_post_queue_limit">postscreen_post_queue_limit</a> ($<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b> <b><a href="postconf.5.html#postscreen_post_queue_limit">postscreen_post_queue_limit</a> ($<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b>
The number of clients that can be waiting for ser- The number of clients that can be waiting for ser-
vice from a real SMTP server process. vice from a real SMTP server process.
<b><a href="postconf.5.html#postscreen_pre_queue_limit">postscreen_pre_queue_limit</a> ($<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b> <b><a href="postconf.5.html#postscreen_pre_queue_limit">postscreen_pre_queue_limit</a> ($<a href="postconf.5.html#default_process_limit">default_process_limit</a>)</b>
The number of non-whitelisted clients that can be The number of non-whitelisted clients that can be
waiting for a decision whether they will receive waiting for a decision whether they will receive
service from a real SMTP server process. service from a real SMTP server process.
<b><a href="postconf.5.html#postscreen_watchdog_timeout">postscreen_watchdog_timeout</a> (10s)</b> <b><a href="postconf.5.html#postscreen_watchdog_timeout">postscreen_watchdog_timeout</a> (10s)</b>
How much time a <a href="postscreen.8.html"><b>postscreen</b>(8)</a> process may take to How much time a <a href="postscreen.8.html"><b>postscreen</b>(8)</a> process may take to
respond to an SMTP client command or to perform a respond to an SMTP client command or to perform a
cache operation before it is terminated by a built- cache operation before it is terminated by a built-
in watchdog timer. in watchdog timer.
<b>STARTTLS CONTROLS</b> <b>STARTTLS CONTROLS</b>
<b><a href="postconf.5.html#postscreen_tls_security_level">postscreen_tls_security_level</a> ($<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a>)</b> <b><a href="postconf.5.html#postscreen_tls_security_level">postscreen_tls_security_level</a> ($<a href="postconf.5.html#smtpd_tls_security_level">smtpd_tls_security_level</a>)</b>
The SMTP TLS security level for the <a href="postscreen.8.html"><b>postscreen</b>(8)</a> The SMTP TLS security level for the <a href="postscreen.8.html"><b>postscreen</b>(8)</a>
server; when a non-empty value is specified, this server; when a non-empty value is specified, this
overrides the obsolete parameters overrides the obsolete parameters
<a href="postconf.5.html#postscreen_use_tls">postscreen_use_tls</a> and <a href="postconf.5.html#postscreen_enforce_tls">postscreen_enforce_tls</a>. <a href="postconf.5.html#postscreen_use_tls">postscreen_use_tls</a> and <a href="postconf.5.html#postscreen_enforce_tls">postscreen_enforce_tls</a>.
<b><a href="postconf.5.html#tlsproxy_service_name">tlsproxy_service_name</a> (tlsproxy)</b> <b><a href="postconf.5.html#tlsproxy_service_name">tlsproxy_service_name</a> (tlsproxy)</b>
The name of the <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> service entry in mas- The name of the <a href="tlsproxy.8.html"><b>tlsproxy</b>(8)</a> service entry in mas-
ter.cf. ter.cf.
<b>OBSOLETE STARTTLS SUPPORT CONTROLS</b> <b>OBSOLETE STARTTLS SUPPORT CONTROLS</b>
These parameters are supported for compatibility with These parameters are supported for compatibility with
<a href="smtpd.8.html"><b>smtpd</b>(8)</a> legacy parameters. <a href="smtpd.8.html"><b>smtpd</b>(8)</a> legacy parameters.
<b><a href="postconf.5.html#postscreen_use_tls">postscreen_use_tls</a> ($<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a>)</b> <b><a href="postconf.5.html#postscreen_use_tls">postscreen_use_tls</a> ($<a href="postconf.5.html#smtpd_use_tls">smtpd_use_tls</a>)</b>
Opportunistic TLS: announce STARTTLS support to Opportunistic TLS: announce STARTTLS support to
SMTP clients, but do not require that clients use SMTP clients, but do not require that clients use
TLS encryption. TLS encryption.
<b><a href="postconf.5.html#postscreen_enforce_tls">postscreen_enforce_tls</a> ($<a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>)</b> <b><a href="postconf.5.html#postscreen_enforce_tls">postscreen_enforce_tls</a> ($<a href="postconf.5.html#smtpd_enforce_tls">smtpd_enforce_tls</a>)</b>
Mandatory TLS: announce STARTTLS support to SMTP Mandatory TLS: announce STARTTLS support to SMTP
clients, and require that clients use TLS encryp- clients, and require that clients use TLS encryp-
tion. tion.
<b>TROUBLE SHOOTING CONTROLS</b>
<b><a href="postconf.5.html#postscreen_expansion_filter">postscreen_expansion_filter</a> (see 'postconf -d' output)</b>
List of characters that are permitted in
<a href="postconf.5.html#postscreen_reject_footer">postscreen_reject_footer</a> attribute expansions.
<b><a href="postconf.5.html#postscreen_reject_footer">postscreen_reject_footer</a> ($<a href="postconf.5.html#smtpd_reject_footer">smtpd_reject_footer</a>)</b>
Optional information that is appended after a 4XX
or 5XX server response.
<b>MISCELLANEOUS CONTROLS</b> <b>MISCELLANEOUS CONTROLS</b>
<b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</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 The default location of the Postfix <a href="postconf.5.html">main.cf</a> and
<a href="master.5.html">master.cf</a> configuration files. <a href="master.5.html">master.cf</a> configuration files.
<b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b> <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 The maximal number of digits after the decimal
point when logging sub-second delay values. point when logging sub-second delay values.
<b><a href="postconf.5.html#command_directory">command_directory</a> (see 'postconf -d' output)</b> <b><a href="postconf.5.html#command_directory">command_directory</a> (see 'postconf -d' output)</b>
The location of all postfix administrative com- The location of all postfix administrative com-
mands. mands.
<b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b> <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
The maximum amount of time that an idle Postfix The maximum amount of time that an idle Postfix
daemon process waits for an incoming connection daemon process waits for an incoming connection
before terminating voluntarily. before terminating voluntarily.
<b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b> <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
The process ID of a Postfix command or daemon The process ID of a Postfix command or daemon
process. process.
<b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b> <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
The process name of a Postfix command or daemon The process name of a Postfix command or daemon
process. process.
<b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b> <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
The syslog facility of Postfix logging. The syslog facility of Postfix logging.
<b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b> <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
The mail system name that is prepended to the The mail system name that is prepended to the
process name in syslog records, so that "smtpd" process name in syslog records, so that "smtpd"
becomes, for example, "postfix/smtpd". becomes, for example, "postfix/smtpd".
<b>SEE ALSO</b> <b>SEE ALSO</b>
@@ -387,12 +400,14 @@ POSTSCREEN(8) POSTSCREEN(8)
<a href="POSTSCREEN_README.html">POSTSCREEN_README</a>, Postfix Postscreen Howto <a href="POSTSCREEN_README.html">POSTSCREEN_README</a>, Postfix Postscreen Howto
<b>LICENSE</b> <b>LICENSE</b>
The Secure Mailer license must be distributed with this The Secure Mailer license must be distributed with this
software. software.
<b>HISTORY</b> <b>HISTORY</b>
Many ideas in <a href="postscreen.8.html"><b>postscreen</b>(8)</a> were explored in earlier work This service was introduced with Postfix version 2.8.
by Michael Tokarev, in OpenBSD spamd, and in MailChannels
Many ideas in <a href="postscreen.8.html"><b>postscreen</b>(8)</a> were explored in earlier work
by Michael Tokarev, in OpenBSD spamd, and in MailChannels
Traffic Control. Traffic Control.
<b>AUTHOR(S)</b> <b>AUTHOR(S)</b>

23
postfix/man/man5/postconf.5
View File

@@ -3729,7 +3729,7 @@ and enabled instances are processed in reverse order.
.PP .PP
This feature is available in Postfix 2.6 and later. This feature is available in Postfix 2.6 and later.
.SH postscreen_access_list (default: permit_mynetworks) .SH postscreen_access_list (default: permit_mynetworks)
Permanent white/blacklist for remote SMTP client IP addresses; Permanent white/blacklist for remote SMTP client IP addresses.
\fBpostscreen\fR(8) searches this list immediately after a remote SMTP \fBpostscreen\fR(8) searches this list immediately after a remote SMTP
client connects. Specify a comma- or whitespace-separated list of client connects. Specify a comma- or whitespace-separated list of
commands (in upper or lower case) or lookup tables. The search stops commands (in upper or lower case) or lookup tables. The search stops
@@ -3757,11 +3757,16 @@ Blacklist the client and terminate
the search. Subject the client to the action configured with the the search. Subject the client to the action configured with the
postscreen_blacklist_action configuration parameter. postscreen_blacklist_action configuration parameter.
.IP "\fB dunno \fR" .IP "\fB dunno \fR"
When used inside a lookup table, All \fBpostscreen\fR(8) access lists
return from the lookup table and evaluate the next command. implicitly have this command at the end.
.br .br
When used outside a lookup table, terminate the search, and subject When \fB dunno \fR
the client to the configured before/after 220 greeting tests. is executed inside a lookup table, return from the lookup table and
evaluate the next command.
.br
When \fB dunno \fR is executed
outside a lookup table, terminate the search, and subject the client
to the configured before/after 220 greeting tests.
.PP .PP
Example: Example:
.PP .PP
@@ -3827,8 +3832,8 @@ one-letter suffix that specifies the time unit). Time units: s
This feature is available in Postfix 2.8. This feature is available in Postfix 2.8.
.SH postscreen_blacklist_action (default: ignore) .SH postscreen_blacklist_action (default: ignore)
The action that \fBpostscreen\fR(8) takes when an SMTP client is The action that \fBpostscreen\fR(8) takes when an SMTP client is
permanently blacklisted with the postscreen_blacklist_networks permanently blacklisted with the postscreen_access_list parameter.
parameter. Specify one of the following: Specify one of the following:
.IP "\fBignore\fR (default)" .IP "\fBignore\fR (default)"
Ignore this result. Allow other tests to complete. Repeat Ignore this result. Allow other tests to complete. Repeat
this test the next time the client connects. this test the next time the client connects.
@@ -3898,8 +3903,8 @@ See smtpd_command_filter for further details.
.PP .PP
This feature is available in Postfix 2.8 and later. This feature is available in Postfix 2.8 and later.
.SH postscreen_command_time_limit (default: ${stress?10}${stress:300}s) .SH postscreen_command_time_limit (default: ${stress?10}${stress:300}s)
The command "read" time limit for \fBpostscreen\fR(8)'s built-in SMTP The time limit to read an entire command line with \fBpostscreen\fR(8)'s
protocol engine. This bounds the time to receive an entire command. built-in SMTP protocol engine.
.PP .PP
This feature is available in Postfix 2.8. This feature is available in Postfix 2.8.
.SH postscreen_disable_vrfy_command (default: $disable_vrfy_command) .SH postscreen_disable_vrfy_command (default: $disable_vrfy_command)

10
postfix/man/man8/dnsblog.8
View File

@@ -13,10 +13,14 @@ Postfix DNS white/blacklist logger
.ad .ad
.fi .fi
The \fBdnsblog\fR(8) server implements an ad-hoc DNS The \fBdnsblog\fR(8) server implements an ad-hoc DNS
white/blacklist lookup service that will eventually be white/blacklist lookup service. This may eventually be
replaced by an UDP client that is built directly into the replaced by an UDP client that is built directly into the
\fBpostscreen\fR(8) server. \fBpostscreen\fR(8) server.
.SH "PROTOCOL"
.na
.nf
.ad
.fi
With each connection, the \fBdnsblog\fR(8) server receives With each connection, the \fBdnsblog\fR(8) server receives
a DNS white/blacklist domain name and an IP address. If the a DNS white/blacklist domain name and an IP address. If the
address is listed under the DNS white/blacklist, the address is listed under the DNS white/blacklist, the
@@ -80,7 +84,7 @@ The Secure Mailer license must be distributed with this software.
.nf .nf
.ad .ad
.fi .fi
This service is temporary with Postfix version 2.7. This service was introduced with Postfix version 2.8.
.SH "AUTHOR(S)" .SH "AUTHOR(S)"
.na .na
.nf .nf

83
postfix/man/man8/postscreen.8
View File

@@ -76,9 +76,6 @@ Problems and transactions are logged to \fBsyslogd\fR(8).
.SH BUGS .SH BUGS
.ad .ad
.fi .fi
The \fBpostscreen\fR(8) server does not yet implement
the \fBsoft_bounce\fR feature.
The \fBpostscreen\fR(8) built-in SMTP protocol engine The \fBpostscreen\fR(8) built-in SMTP protocol engine
currently does not announce support for AUTH, XCLIENT or currently does not announce support for AUTH, XCLIENT or
XFORWARD. XFORWARD.
@@ -135,24 +132,46 @@ to a remote SMTP client.
A case insensitive list of EHLO keywords (pipelining, starttls, A case insensitive list of EHLO keywords (pipelining, starttls,
auth, etc.) that the \fBpostscreen\fR(8) server will not send in the EHLO auth, etc.) that the \fBpostscreen\fR(8) server will not send in the EHLO
response to a remote SMTP client. response to a remote SMTP client.
.SH "BEFORE-GREETING TRIAGE" .SH "TROUBLE SHOOTING CONTROLS"
.na .na
.nf .nf
.ad .ad
.fi .fi
.IP "\fBdnsblog_service_name (dnsblog)\fR" .IP "\fBpostscreen_expansion_filter (see 'postconf -d' output)\fR"
The name of the \fBdnsblog\fR(8) service entry in master.cf. List of characters that are permitted in postscreen_reject_footer
attribute expansions.
.IP "\fBpostscreen_reject_footer ($smtpd_reject_footer)\fR"
Optional information that is appended after a 4XX or 5XX server
response.
.IP "\fBsoft_bounce (no)\fR"
Safety net to keep mail queued that would otherwise be returned to
the sender.
.SH "PERMANENT WHITE/BLACKLIST TEST"
.na
.nf
.ad
.fi
This test is executed immediately after a remote SMTP client
connects. If a client is permanently whitelisted, the client
will be handed off immediately to a Postfix SMTP server
process.
.IP "\fBpostscreen_access_list (permit_mynetworks)\fR" .IP "\fBpostscreen_access_list (permit_mynetworks)\fR"
Permanent white/blacklist for remote SMTP client IP addresses; Permanent white/blacklist for remote SMTP client IP addresses.
\fBpostscreen\fR(8) searches this list immediately after a remote SMTP
client connects.
.IP "\fBpostscreen_blacklist_action (ignore)\fR" .IP "\fBpostscreen_blacklist_action (ignore)\fR"
The action that \fBpostscreen\fR(8) takes when an SMTP client is The action that \fBpostscreen\fR(8) takes when an SMTP client is
permanently blacklisted with the postscreen_blacklist_networks permanently blacklisted with the postscreen_access_list parameter.
parameter. .SH "BEFORE-GREETING TESTS"
.IP "\fBpostscreen_blacklist_networks (empty)\fR" .na
Network addresses that are permanently blacklisted; see the .nf
postscreen_blacklist_action parameter for possible actions. .ad
.fi
These tests are executed before the remote SMTP client
receives the "220 servername" greeting. If no tests remain
after the successful completion of this phase, the client
will be handed off immediately to a Postfix SMTP server
process.
.IP "\fBdnsblog_service_name (dnsblog)\fR"
The name of the \fBdnsblog\fR(8) service entry in master.cf.
.IP "\fBpostscreen_dnsbl_action (ignore)\fR" .IP "\fBpostscreen_dnsbl_action (ignore)\fR"
The action that \fBpostscreen\fR(8) takes when an SMTP client's combined The action that \fBpostscreen\fR(8) takes when an SMTP client's combined
DNSBL score is equal to or greater than a threshold (as defined DNSBL score is equal to or greater than a threshold (as defined
@@ -184,11 +203,20 @@ The amount of time that \fBpostscreen\fR(8) will wait for an SMTP
client to send a command before its turn, and for DNS blocklist client to send a command before its turn, and for DNS blocklist
lookup results to arrive (default: up to 2 seconds under stress, lookup results to arrive (default: up to 2 seconds under stress,
up to 6 seconds otherwise). up to 6 seconds otherwise).
.SH "AFTER-GREETING TRIAGE" .IP "\fBsmtpd_service_name (smtpd)\fR"
The internal service that \fBpostscreen\fR(8) forwards allowed
connections to.
.SH "AFTER-GREETING TESTS"
.na .na
.nf .nf
.ad .ad
.fi .fi
These tests are executed after the remote SMTP client
receives the "220 servername" greeting. If a client passes
all tests during this phase, it will receive a 4XX response
to RCPT TO commands until the client hangs up. After this,
the client will be allowed to talk directly to a Postfix
SMTP server process.
.IP "\fBpostscreen_bare_newline_action (ignore)\fR" .IP "\fBpostscreen_bare_newline_action (ignore)\fR"
The action that \fBpostscreen\fR(8) takes when an SMTP client sends The action that \fBpostscreen\fR(8) takes when an SMTP client sends
a bare newline character, that is, a newline not preceded by carriage a bare newline character, that is, a newline not preceded by carriage
@@ -217,14 +245,6 @@ the server to respond.
.IP "\fBpostscreen_pipelining_enable (no)\fR" .IP "\fBpostscreen_pipelining_enable (no)\fR"
Enable "pipelining" SMTP protocol tests in the \fBpostscreen\fR(8) Enable "pipelining" SMTP protocol tests in the \fBpostscreen\fR(8)
server. server.
.SH "AFTER-TRIAGE CONTROLS"
.na
.nf
.ad
.fi
.IP "\fBsmtpd_service_name (smtpd)\fR"
The internal service that \fBpostscreen\fR(8) forwards allowed
connections to.
.SH "CACHE CONTROLS" .SH "CACHE CONTROLS"
.na .na
.nf .nf
@@ -267,8 +287,8 @@ with the \fBpostscreen\fR(8) daemon.
The limit on the total number of commands per SMTP session for The limit on the total number of commands per SMTP session for
\fBpostscreen\fR(8)'s built-in SMTP protocol engine. \fBpostscreen\fR(8)'s built-in SMTP protocol engine.
.IP "\fBpostscreen_command_time_limit (${stress?10}${stress:300}s)\fR" .IP "\fBpostscreen_command_time_limit (${stress?10}${stress:300}s)\fR"
The command "read" time limit for \fBpostscreen\fR(8)'s built-in SMTP The time limit to read an entire command line with \fBpostscreen\fR(8)'s
protocol engine. built-in SMTP protocol engine.
.IP "\fBpostscreen_post_queue_limit ($default_process_limit)\fR" .IP "\fBpostscreen_post_queue_limit ($default_process_limit)\fR"
The number of clients that can be waiting for service from a The number of clients that can be waiting for service from a
real SMTP server process. real SMTP server process.
@@ -304,17 +324,6 @@ but do not require that clients use TLS encryption.
.IP "\fBpostscreen_enforce_tls ($smtpd_enforce_tls)\fR" .IP "\fBpostscreen_enforce_tls ($smtpd_enforce_tls)\fR"
Mandatory TLS: announce STARTTLS support to SMTP clients, and Mandatory TLS: announce STARTTLS support to SMTP clients, and
require that clients use TLS encryption. require that clients use TLS encryption.
.SH "TROUBLE SHOOTING CONTROLS"
.na
.nf
.ad
.fi
.IP "\fBpostscreen_expansion_filter (see 'postconf -d' output)\fR"
List of characters that are permitted in postscreen_reject_footer
attribute expansions.
.IP "\fBpostscreen_reject_footer ($smtpd_reject_footer)\fR"
Optional information that is appended after a 4XX or 5XX server
response.
.SH "MISCELLANEOUS CONTROLS" .SH "MISCELLANEOUS CONTROLS"
.na .na
.nf .nf
@@ -368,6 +377,8 @@ The Secure Mailer license must be distributed with this software.
.nf .nf
.ad .ad
.fi .fi
This service was introduced with Postfix version 2.8.
Many ideas in \fBpostscreen\fR(8) were explored in earlier Many ideas in \fBpostscreen\fR(8) were explored in earlier
work by Michael Tokarev, in OpenBSD spamd, and in MailChannels work by Michael Tokarev, in OpenBSD spamd, and in MailChannels
Traffic Control. Traffic Control.

56
postfix/proto/POSTSCREEN_README.html
View File

@@ -28,18 +28,18 @@ mail from end-user clients (MUAs). In a typical deployment,
postscreen(8) is used on the "port 25" service, while MUA clients postscreen(8) is used on the "port 25" service, while MUA clients
submit mail via the submission service. </p> submit mail via the submission service. </p>
<p> postscreen(8) is the first layer in a multi-layer defense. <p> <p> postscreen(8) is part of a multi-layer defense. <p>
<ul> <ul>
<li> <p> The postscreen(8) layer blocks connections from zombies <li> <p> As the first layer, postscreen(8) blocks connections from
and other spambots that are responsible for about 90% of all spam. zombies and other spambots that are responsible for about 90% of
It is implemented as a single process to make this defense as cheap all spam. It is implemented as a single process to make this defense
as possible. </p> as cheap as possible. </p>
<li> <p> The second layer implements more complex SMTP-level access <li> <p> The second layer implements more complex SMTP-level access
checks that are available with Postfix SMTP servers, policy daemons, checks with Postfix SMTP servers, policy daemons, and Milter
and Milter applications. </p> applications. </p>
<li> <p> The third layer performs light-weight content inspection <li> <p> The third layer performs light-weight content inspection
with the Postfix built-in header_checks and body_checks. This can with the Postfix built-in header_checks and body_checks. This can
@@ -672,6 +672,23 @@ without blocking mail: </p>
<ol> <ol>
<li> <p> Make sure that local clients and systems with non-standard
SMTP implementations are excluded from any postscreen(8) tests. The
default is to exclude all clients in mynetworks. To exclude additional
clients, for example, third-party performance monitoring tools (these
tend to have broken SMTP implementations): </p>
<pre>
/etc/postfix/main.cf:
# Exclude broken clients by whitelisting. Clients in mynetworks
# should always be whitelisted.
postscreen_access_list = permit_mynetworks,
cidr:/etc/postfix/postscreen_access.cidr
/etc/postfix/postscreen_access.cidr:
192.168.254.0/24 permit
</pre>
<li> <p> Comment out the "<tt>smtp inet ... smtpd</tt>" service <li> <p> Comment out the "<tt>smtp inet ... smtpd</tt>" service
in master.cf, including any "<tt>-o parameter=value</tt>" entries in master.cf, including any "<tt>-o parameter=value</tt>" entries
that follow. </p> that follow. </p>
@@ -768,10 +785,6 @@ string. </p>
greeting</a>" for details about the logging from these postscreen(8) greeting</a>" for details about the logging from these postscreen(8)
tests. </p> tests. </p>
<li> <p> By default, postscreen(8) whitelists all clients in
mynetworks. This is a safety feature to avoid you from getting
into trouble with local users. </p>
<li> <p> If you run Postfix 2.6 or earlier you must stop and start <li> <p> If you run Postfix 2.6 or earlier you must stop and start
the master daemon ("<tt>postfix stop; postfix start</tt>"). This the master daemon ("<tt>postfix stop; postfix start</tt>"). This
is needed because the Postfix "pass" master service type did not is needed because the Postfix "pass" master service type did not
@@ -802,6 +815,27 @@ services. </p>
<h3> <a name="blocking"> Blocking mail with postscreen(8) </a> </h3> <h3> <a name="blocking"> Blocking mail with postscreen(8) </a> </h3>
<p> For compatibility with smtpd(8), postscreen(8) implements the
soft_bounce safety feature. This causes Postfix to reject mail with
a "try again" reply code. </p>
<ul>
<li> <p> To turn this on for all of Postfix, specify "<tt>soft_bounce
= yes</tt>" in main.cf. </p>
<li> <p> To turn this on for postscreen(8) only, append "<tt>-o
soft_bounce=yes</tt>" (note: NO SPACES around '=') to the postscreen
entry in master.cf. <p>
</ul>
<p> Execute "<tt>postfix reload</tt>" to make the change effective. </p>
<p> After testing, do not forget to remove the soft_bounce feature,
otherwise senders won't receive their non-delivery notification
until many days later. </p>
<p> To use the postscreen(8) service to block mail, edit main.cf and <p> To use the postscreen(8) service to block mail, edit main.cf and
specify one or more of: </p> specify one or more of: </p>

21
postfix/proto/postconf.proto
View File

@@ -12831,7 +12831,7 @@ IP address. </p>
%PARAM postscreen_access_list permit_mynetworks %PARAM postscreen_access_list permit_mynetworks
<p> Permanent white/blacklist for remote SMTP client IP addresses; <p> Permanent white/blacklist for remote SMTP client IP addresses.
postscreen(8) searches this list immediately after a remote SMTP postscreen(8) searches this list immediately after a remote SMTP
client connects. Specify a comma- or whitespace-separated list of client connects. Specify a comma- or whitespace-separated list of
commands (in upper or lower case) or lookup tables. The search stops commands (in upper or lower case) or lookup tables. The search stops
@@ -12861,10 +12861,12 @@ server process. </dd>
the search. Subject the client to the action configured with the the search. Subject the client to the action configured with the
postscreen_blacklist_action configuration parameter. </dd> postscreen_blacklist_action configuration parameter. </dd>
<dt> <b> dunno </b> </dt> <dd> When used inside a lookup table, <dt> <b> dunno </b> </dt> <dd> All postscreen(8) access lists
return from the lookup table and evaluate the next command. <br> implicitly have this command at the end. <br> When <b> dunno </b>
When used outside a lookup table, terminate the search, and subject is executed inside a lookup table, return from the lookup table and
the client to the configured before/after 220 greeting tests. </dd> evaluate the next command. <br> When <b> dunno </b> is executed
outside a lookup table, terminate the search, and subject the client
to the configured before/after 220 greeting tests. </dd>
</dl> </dl>
@@ -12900,8 +12902,8 @@ value to disable this feature. </p>
%PARAM postscreen_blacklist_action ignore %PARAM postscreen_blacklist_action ignore
<p> The action that postscreen(8) takes when an SMTP client is <p> The action that postscreen(8) takes when an SMTP client is
permanently blacklisted with the postscreen_blacklist_networks permanently blacklisted with the postscreen_access_list parameter.
parameter. Specify one of the following: </p> Specify one of the following: </p>
<dl> <dl>
@@ -13178,9 +13180,8 @@ and error commands. </p>
%PARAM postscreen_command_time_limit ${stress?10}${stress:300}s %PARAM postscreen_command_time_limit ${stress?10}${stress:300}s
<p> The command "read" time limit for postscreen(8)'s built-in SMTP <p> The time limit to read an entire command line with postscreen(8)'s
protocol engine. This bounds the time to receive an entire command. built-in SMTP protocol engine. </p>
</p>
<p> This feature is available in Postfix 2.8. </p> <p> This feature is available in Postfix 2.8. </p>

8
postfix/src/dnsblog/dnsblog.c
View File

@@ -7,10 +7,12 @@
/* \fBdnsblog\fR [generic Postfix daemon options] /* \fBdnsblog\fR [generic Postfix daemon options]
/* DESCRIPTION /* DESCRIPTION
/* The \fBdnsblog\fR(8) server implements an ad-hoc DNS /* The \fBdnsblog\fR(8) server implements an ad-hoc DNS
/* white/blacklist lookup service that will eventually be /* white/blacklist lookup service. This may eventually be
/* replaced by an UDP client that is built directly into the /* replaced by an UDP client that is built directly into the
/* \fBpostscreen\fR(8) server. /* \fBpostscreen\fR(8) server.
/* /* PROTOCOL
/* .ad
/* .fi
/* With each connection, the \fBdnsblog\fR(8) server receives /* With each connection, the \fBdnsblog\fR(8) server receives
/* a DNS white/blacklist domain name and an IP address. If the /* a DNS white/blacklist domain name and an IP address. If the
/* address is listed under the DNS white/blacklist, the /* address is listed under the DNS white/blacklist, the
@@ -64,7 +66,7 @@
/* HISTORY /* HISTORY
/* .ad /* .ad
/* .fi /* .fi
/* This service is temporary with Postfix version 2.7. /* This service was introduced with Postfix version 2.8.
/* AUTHOR(S) /* AUTHOR(S)
/* Wietse Venema /* Wietse Venema
/* IBM T.J. Watson Research /* IBM T.J. Watson Research

4
postfix/src/global/mail_version.h
View File

@@ -20,8 +20,8 @@
* Patches change both the patchlevel and the release date. Snapshots have no * Patches change both the patchlevel and the release date. Snapshots have no
* patchlevel; they change the release date only. * patchlevel; they change the release date only.
*/ */
#define MAIL_RELEASE_DATE "20110115" #define MAIL_RELEASE_DATE "20110116"
#define MAIL_VERSION_NUMBER "2.8" #define MAIL_VERSION_NUMBER "2.9"
#ifdef SNAPSHOT #ifdef SNAPSHOT
# define MAIL_VERSION_DATE "-" MAIL_RELEASE_DATE # define MAIL_VERSION_DATE "-" MAIL_RELEASE_DATE

75
postfix/src/postscreen/postscreen.c
View File

@@ -62,9 +62,6 @@
/* DIAGNOSTICS /* DIAGNOSTICS
/* Problems and transactions are logged to \fBsyslogd\fR(8). /* Problems and transactions are logged to \fBsyslogd\fR(8).
/* BUGS /* BUGS
/* The \fBpostscreen\fR(8) server does not yet implement
/* the \fBsoft_bounce\fR feature.
/*
/* The \fBpostscreen\fR(8) built-in SMTP protocol engine /* The \fBpostscreen\fR(8) built-in SMTP protocol engine
/* currently does not announce support for AUTH, XCLIENT or /* currently does not announce support for AUTH, XCLIENT or
/* XFORWARD. /* XFORWARD.
@@ -117,22 +114,40 @@
/* A case insensitive list of EHLO keywords (pipelining, starttls, /* A case insensitive list of EHLO keywords (pipelining, starttls,
/* auth, etc.) that the \fBpostscreen\fR(8) server will not send in the EHLO /* auth, etc.) that the \fBpostscreen\fR(8) server will not send in the EHLO
/* response to a remote SMTP client. /* response to a remote SMTP client.
/* BEFORE-GREETING TRIAGE /* TROUBLE SHOOTING CONTROLS
/* .ad /* .ad
/* .fi /* .fi
/* .IP "\fBdnsblog_service_name (dnsblog)\fR" /* .IP "\fBpostscreen_expansion_filter (see 'postconf -d' output)\fR"
/* The name of the \fBdnsblog\fR(8) service entry in master.cf. /* List of characters that are permitted in postscreen_reject_footer
/* attribute expansions.
/* .IP "\fBpostscreen_reject_footer ($smtpd_reject_footer)\fR"
/* Optional information that is appended after a 4XX or 5XX server
/* response.
/* .IP "\fBsoft_bounce (no)\fR"
/* Safety net to keep mail queued that would otherwise be returned to
/* the sender.
/* PERMANENT WHITE/BLACKLIST TEST
/* .ad
/* .fi
/* This test is executed immediately after a remote SMTP client
/* connects. If a client is permanently whitelisted, the client
/* will be handed off immediately to a Postfix SMTP server
/* process.
/* .IP "\fBpostscreen_access_list (permit_mynetworks)\fR" /* .IP "\fBpostscreen_access_list (permit_mynetworks)\fR"
/* Permanent white/blacklist for remote SMTP client IP addresses; /* Permanent white/blacklist for remote SMTP client IP addresses.
/* \fBpostscreen\fR(8) searches this list immediately after a remote SMTP
/* client connects.
/* .IP "\fBpostscreen_blacklist_action (ignore)\fR" /* .IP "\fBpostscreen_blacklist_action (ignore)\fR"
/* The action that \fBpostscreen\fR(8) takes when an SMTP client is /* The action that \fBpostscreen\fR(8) takes when an SMTP client is
/* permanently blacklisted with the postscreen_blacklist_networks /* permanently blacklisted with the postscreen_access_list parameter.
/* parameter. /* BEFORE-GREETING TESTS
/* .IP "\fBpostscreen_blacklist_networks (empty)\fR" /* .ad
/* Network addresses that are permanently blacklisted; see the /* .fi
/* postscreen_blacklist_action parameter for possible actions. /* These tests are executed before the remote SMTP client
/* receives the "220 servername" greeting. If no tests remain
/* after the successful completion of this phase, the client
/* will be handed off immediately to a Postfix SMTP server
/* process.
/* .IP "\fBdnsblog_service_name (dnsblog)\fR"
/* The name of the \fBdnsblog\fR(8) service entry in master.cf.
/* .IP "\fBpostscreen_dnsbl_action (ignore)\fR" /* .IP "\fBpostscreen_dnsbl_action (ignore)\fR"
/* The action that \fBpostscreen\fR(8) takes when an SMTP client's combined /* The action that \fBpostscreen\fR(8) takes when an SMTP client's combined
/* DNSBL score is equal to or greater than a threshold (as defined /* DNSBL score is equal to or greater than a threshold (as defined
@@ -164,9 +179,18 @@
/* client to send a command before its turn, and for DNS blocklist /* client to send a command before its turn, and for DNS blocklist
/* lookup results to arrive (default: up to 2 seconds under stress, /* lookup results to arrive (default: up to 2 seconds under stress,
/* up to 6 seconds otherwise). /* up to 6 seconds otherwise).
/* AFTER-GREETING TRIAGE /* .IP "\fBsmtpd_service_name (smtpd)\fR"
/* The internal service that \fBpostscreen\fR(8) forwards allowed
/* connections to.
/* AFTER-GREETING TESTS
/* .ad /* .ad
/* .fi /* .fi
/* These tests are executed after the remote SMTP client
/* receives the "220 servername" greeting. If a client passes
/* all tests during this phase, it will receive a 4XX response
/* to RCPT TO commands until the client hangs up. After this,
/* the client will be allowed to talk directly to a Postfix
/* SMTP server process.
/* .IP "\fBpostscreen_bare_newline_action (ignore)\fR" /* .IP "\fBpostscreen_bare_newline_action (ignore)\fR"
/* The action that \fBpostscreen\fR(8) takes when an SMTP client sends /* The action that \fBpostscreen\fR(8) takes when an SMTP client sends
/* a bare newline character, that is, a newline not preceded by carriage /* a bare newline character, that is, a newline not preceded by carriage
@@ -195,12 +219,6 @@
/* .IP "\fBpostscreen_pipelining_enable (no)\fR" /* .IP "\fBpostscreen_pipelining_enable (no)\fR"
/* Enable "pipelining" SMTP protocol tests in the \fBpostscreen\fR(8) /* Enable "pipelining" SMTP protocol tests in the \fBpostscreen\fR(8)
/* server. /* server.
/* AFTER-TRIAGE CONTROLS
/* .ad
/* .fi
/* .IP "\fBsmtpd_service_name (smtpd)\fR"
/* The internal service that \fBpostscreen\fR(8) forwards allowed
/* connections to.
/* CACHE CONTROLS /* CACHE CONTROLS
/* .ad /* .ad
/* .fi /* .fi
@@ -239,8 +257,8 @@
/* The limit on the total number of commands per SMTP session for /* The limit on the total number of commands per SMTP session for
/* \fBpostscreen\fR(8)'s built-in SMTP protocol engine. /* \fBpostscreen\fR(8)'s built-in SMTP protocol engine.
/* .IP "\fBpostscreen_command_time_limit (${stress?10}${stress:300}s)\fR" /* .IP "\fBpostscreen_command_time_limit (${stress?10}${stress:300}s)\fR"
/* The command "read" time limit for \fBpostscreen\fR(8)'s built-in SMTP /* The time limit to read an entire command line with \fBpostscreen\fR(8)'s
/* protocol engine. /* built-in SMTP protocol engine.
/* .IP "\fBpostscreen_post_queue_limit ($default_process_limit)\fR" /* .IP "\fBpostscreen_post_queue_limit ($default_process_limit)\fR"
/* The number of clients that can be waiting for service from a /* The number of clients that can be waiting for service from a
/* real SMTP server process. /* real SMTP server process.
@@ -272,15 +290,6 @@
/* .IP "\fBpostscreen_enforce_tls ($smtpd_enforce_tls)\fR" /* .IP "\fBpostscreen_enforce_tls ($smtpd_enforce_tls)\fR"
/* Mandatory TLS: announce STARTTLS support to SMTP clients, and /* Mandatory TLS: announce STARTTLS support to SMTP clients, and
/* require that clients use TLS encryption. /* require that clients use TLS encryption.
/* TROUBLE SHOOTING CONTROLS
/* .ad
/* .fi
/* .IP "\fBpostscreen_expansion_filter (see 'postconf -d' output)\fR"
/* List of characters that are permitted in postscreen_reject_footer
/* attribute expansions.
/* .IP "\fBpostscreen_reject_footer ($smtpd_reject_footer)\fR"
/* Optional information that is appended after a 4XX or 5XX server
/* response.
/* MISCELLANEOUS CONTROLS /* MISCELLANEOUS CONTROLS
/* .ad /* .ad
/* .fi /* .fi
@@ -324,6 +333,8 @@
/* HISTORY /* HISTORY
/* .ad /* .ad
/* .fi /* .fi
/* This service was introduced with Postfix version 2.8.
/*
/* Many ideas in \fBpostscreen\fR(8) were explored in earlier /* Many ideas in \fBpostscreen\fR(8) were explored in earlier
/* work by Michael Tokarev, in OpenBSD spamd, and in MailChannels /* work by Michael Tokarev, in OpenBSD spamd, and in MailChannels
/* Traffic Control. /* Traffic Control.

26
postfix/src/postscreen/postscreen_send.c
View File

@@ -22,6 +22,10 @@
/* a warning (except EPIPE) with the client address and port, /* a warning (except EPIPE) with the client address and port,
/* and returns a non-zero result (all errors including EPIPE). /* and returns a non-zero result (all errors including EPIPE).
/* /*
/* psc_send_reply() does a best effort to send the reply, but
/* it won't block when the output is throttled by a hostile
/* peer.
/*
/* PSC_SEND_REPLY() is a legacy wrapper for psc_send_reply(). /* PSC_SEND_REPLY() is a legacy wrapper for psc_send_reply().
/* It will eventually be replaced by its expansion. /* It will eventually be replaced by its expansion.
/* /*
@@ -88,26 +92,26 @@ int psc_send_reply(PSC_STATE *state, const char *text)
*/ */
start = VSTRING_LEN(state->send_buf); start = VSTRING_LEN(state->send_buf);
vstring_strcat(state->send_buf, text); vstring_strcat(state->send_buf, text);
if (*var_psc_rej_footer && (*text == '4' || *text == '5'))
smtp_reply_footer(state->send_buf, start, var_psc_rej_footer,
STR(psc_expand_filter), psc_expand_lookup,
(char *) state);
/* /*
* XXX For soft_bounce support, it is not sufficient to fix replies here. * For soft_bounce support, we also fix the REJECT logging before the
* We also need to fix the REJECT messages that are logged by the dummy * dummy SMTP engine calls the psc_send_reply() output routine. We do
* SMTP engine. Those messages are set with the PSC_DROP_SESSION_STATE * some double work, but it is for debugging only.
* and PSC_ENFORCE_SESSION_STATE macros, and we should not mess up all
* the code that invokes those macros.
*/ */
#if 0
if (var_soft_bounce) { if (var_soft_bounce) {
if (text[0] == '5') if (text[0] == '5')
STR(state->send_buf)[start + 0] = '4'; STR(state->send_buf)[start + 0] = '4';
if (text[4] == '5') if (text[4] == '5')
STR(state->send_buf)[start + 4] = '4'; STR(state->send_buf)[start + 4] = '4';
} }
#endif
/*
* Append the optional reply footer.
*/
if (*var_psc_rej_footer && (*text == '4' || *text == '5'))
smtp_reply_footer(state->send_buf, start, var_psc_rej_footer,
STR(psc_expand_filter), psc_expand_lookup,
(char *) state);
/* /*
* Do a best effort sending text, but don't block when the output is * Do a best effort sending text, but don't block when the output is

80
postfix/src/postscreen/postscreen_smtpd.c
View File

@@ -24,8 +24,12 @@
/* /*
/* Unlike the Postfix SMTP server, this engine does not announce /* Unlike the Postfix SMTP server, this engine does not announce
/* PIPELINING support. This exposes spambots that pipeline /* PIPELINING support. This exposes spambots that pipeline
/* their commands anyway. To pass this test, the client has /* their commands anyway. Like the Postfix SMTP server, this
/* to speak SMTP all the way to the RCPT TO command. /* engine will accept input with bare newline characters. To
/* pass the "pipelining" and "bare newline" test, the client
/* has to properly speak SMTP all the way to the RCPT TO
/* command. These tests fail if the client violates the protocol
/* at any stage.
/* /*
/* No support is announced for AUTH, XCLIENT or XFORWARD. /* No support is announced for AUTH, XCLIENT or XFORWARD.
/* Clients that need this should be whitelisted or should talk /* Clients that need this should be whitelisted or should talk
@@ -42,10 +46,13 @@
/* a per-session command counter, and terminates the session /* a per-session command counter, and terminates the session
/* with a 421 reply when the command count exceeds the limit. /* with a 421 reply when the command count exceeds the limit.
/* /*
/* We limit the command count so that we don't have to worry /* We limit the command count, as well as the total time to
/* about becoming blocked while sending responses (20 replies /* receive a command. This limits the time per client more
/* of about 40 bytes plus greeting banners). Otherwise we would /* effectively than would be possible with read() timeouts.
/* have to make the output event-driven, just like the input. /*
/* There is no concern about getting blocked on output. The
/* psc_send() routine uses non-blocking output, and discards
/* output that the client is not willing to receive.
/* PROTOCOL INSPECTION VERSUS CONTENT INSPECTION /* PROTOCOL INSPECTION VERSUS CONTENT INSPECTION
/* The goal of postscreen is to keep spambots away from Postfix. /* The goal of postscreen is to keep spambots away from Postfix.
/* To recognize spambots, postscreen measures properties of /* To recognize spambots, postscreen measures properties of
@@ -70,11 +77,11 @@
/* making long-term decisions after single measurements, and /* making long-term decisions after single measurements, and
/* that is why postscreen does not inspect message content. /* that is why postscreen does not inspect message content.
/* REJECTING RCPT TO VERSUS SENDING LIVE SOCKETS TO SMTPD(8) /* REJECTING RCPT TO VERSUS SENDING LIVE SOCKETS TO SMTPD(8)
/* When deep protocol tests are enabled, postscreen rejects /* When post-handshake protocol tests are enabled, postscreen
/* the RCPT TO command from a good client, and forces it to /* rejects the RCPT TO command from a good client, and forces
/* deliver mail in a later session. This is why deep protocol /* it to deliver mail in a later session. This is why
/* tests have a longer expiration time than pre-handshake /* post-handshake protocol tests have a longer expiration time
/* tests. /* than pre-handshake tests.
/* /*
/* Instead, postscreen could send the network socket to smtpd(8) /* Instead, postscreen could send the network socket to smtpd(8)
/* and ship the session history (including TLS and other SMTP /* and ship the session history (including TLS and other SMTP
@@ -188,7 +195,9 @@ static void psc_smtpd_read_event(int, char *);
* Encapsulation. The STARTTLS, EHLO and AUTH command handlers temporarily * Encapsulation. The STARTTLS, EHLO and AUTH command handlers temporarily
* suspend SMTP command events, send an asynchronous proxy request, and * suspend SMTP command events, send an asynchronous proxy request, and
* resume SMTP command events after receiving the asynchrounous proxy * resume SMTP command events after receiving the asynchrounous proxy
* response. * response (the EHLO handler must asynchronously talk to the auth server
* before it can announce the SASL mechanism list; the list can depend on
* the client IP address and on the presence on TLS encryption).
*/ */
#define PSC_RESUME_SMTP_CMD_EVENTS(state) do { \ #define PSC_RESUME_SMTP_CMD_EVENTS(state) do { \
PSC_READ_EVENT_REQUEST2(vstream_fileno((state)->smtp_client_stream), \ PSC_READ_EVENT_REQUEST2(vstream_fileno((state)->smtp_client_stream), \
@@ -411,15 +420,17 @@ static int psc_starttls_cmd(PSC_STATE *state, char *args)
static char *psc_extract_addr(VSTRING *result, const char *string) static char *psc_extract_addr(VSTRING *result, const char *string)
{ {
const unsigned char *cp = (const unsigned char *) string; const unsigned char *cp = (const unsigned char *) string;
char *addr;
char *colon;
int stop_at; int stop_at;
int inquote = 0; int inquote = 0;
/* /*
* smtpd(8) incompatibility: we allow more invalid address forms, and we * smtpd(8) incompatibility: we allow more invalid address forms, and we
* don't strip @site1,site2:user@site3 route addresses. We are not going * don't validate recipients. We are not going to deliver them so we
* to deliver them so we won't have to worry about addresses that end up * won't have to worry about deliverability. This may have to change when
* being nonsense after stripping. This may have to change when we pass * we pass the socket to a real SMTP server and replay message envelope
* the socket to a real SMTP server and replay message envelope commands. * commands.
*/ */
/* Skip SP characters. */ /* Skip SP characters. */
@@ -448,7 +459,15 @@ static char *psc_extract_addr(VSTRING *result, const char *string)
} }
} }
VSTRING_TERMINATE(result); VSTRING_TERMINATE(result);
return (STR(result));
/*
* smtpd(8) compatibility: truncate deprecated route address form. This
* is primarily to simplify logfile analysis.
*/
addr = STR(result);
if (*addr == '@' && (colon = strchr(addr, ':')) != 0)
addr = colon + 1;
return (addr);
} }
/* psc_mail_cmd - record MAIL and respond */ /* psc_mail_cmd - record MAIL and respond */
@@ -478,6 +497,22 @@ static int psc_mail_cmd(PSC_STATE *state, char *args)
return (PSC_SEND_REPLY(state, "250 2.1.0 Ok\r\n")); return (PSC_SEND_REPLY(state, "250 2.1.0 Ok\r\n"));
} }
/* psc_soften_reply - copy and soft-bounce a reply */
static char *psc_soften_reply(const char *reply)
{
static VSTRING *buf = 0;
if (buf == 0)
buf = vstring_alloc(100);
vstring_strcpy(buf, reply);
if (reply[0] == '5')
STR(buf)[0] = '4';
if (reply[4] == '5')
STR(buf)[4] = '4';
return (STR(buf));
}
/* psc_rcpt_cmd record RCPT and respond */ /* psc_rcpt_cmd record RCPT and respond */
static int psc_rcpt_cmd(PSC_STATE *state, char *args) static int psc_rcpt_cmd(PSC_STATE *state, char *args)
@@ -501,7 +536,9 @@ static int psc_rcpt_cmd(PSC_STATE *state, char *args)
msg_info("NOQUEUE: reject: RCPT from [%s]:%s: %.*s; " msg_info("NOQUEUE: reject: RCPT from [%s]:%s: %.*s; "
"from=<%s>, to=<%s>, proto=%s, helo=<%s>", "from=<%s>, to=<%s>, proto=%s, helo=<%s>",
PSC_CLIENT_ADDR_PORT(state), PSC_CLIENT_ADDR_PORT(state),
(int) strlen(state->rcpt_reply) - 2, state->rcpt_reply, (int) strlen(state->rcpt_reply) - 2,
var_soft_bounce == 0 ? state->rcpt_reply :
psc_soften_reply(state->rcpt_reply),
state->sender, addr, state->protocol, state->sender, addr, state->protocol,
state->helo_name ? state->helo_name : ""); state->helo_name ? state->helo_name : "");
return (PSC_SEND_REPLY(state, state->rcpt_reply)); return (PSC_SEND_REPLY(state, state->rcpt_reply));
@@ -700,7 +737,7 @@ static void psc_smtpd_read_event(int event, char *context)
*/ */
/* /*
* Note: on entry into this function the VSTREAM buffer is still empty, * Note: on entry into this function the VSTREAM buffer may be non-empty,
* so we test the "no more input" condition at the bottom of the loops. * so we test the "no more input" condition at the bottom of the loops.
*/ */
for (;;) { for (;;) {
@@ -825,7 +862,8 @@ static void psc_smtpd_read_event(int event, char *context)
/* /*
* Reset the command buffer write pointer and state machine in * Reset the command buffer write pointer and state machine in
* preparation for the next command. For this to work as expected, * preparation for the next command. For this to work as expected,
* VSTRING_RESET() must be non-destructive. * VSTRING_RESET() must be non-destructive. We just can't ask for the
* VSTRING_LEN() and vstring_end() results.
*/ */
state->read_state = PSC_SMTPD_CMD_ST_ANY; state->read_state = PSC_SMTPD_CMD_ST_ANY;
VSTRING_RESET(state->cmd_buffer); VSTRING_RESET(state->cmd_buffer);
@@ -837,7 +875,7 @@ static void psc_smtpd_read_event(int event, char *context)
* session state structure. When this happens we must leave the SMTP * session state structure. When this happens we must leave the SMTP
* engine to avoid a dangling pointer problem. * engine to avoid a dangling pointer problem.
*/ */
cmd_buffer_ptr = vstring_str(state->cmd_buffer); cmd_buffer_ptr = STR(state->cmd_buffer);
if (msg_verbose) if (msg_verbose)
msg_info("< [%s]:%s: %s", state->smtp_client_addr, msg_info("< [%s]:%s: %s", state->smtp_client_addr,
state->smtp_client_port, cmd_buffer_ptr); state->smtp_client_port, cmd_buffer_ptr);