    SOCKETMAP_TABLE(5)                                          SOCKETMAP_TABLE(5)

    NAME
           socketmap_table - Postfix socketmap table lookup client

    SYNOPSIS
           postmap -q "string" socketmap:inet:host:port:name
           postmap -q "string" socketmap:unix:pathname:name

           postmap -q - socketmap:inet:host:port:name <inputfile
           postmap -q - socketmap:unix:pathname:name <inputfile

    DESCRIPTION
           The  Postfix  mail  system  uses optional tables for address rewriting,
           mail routing or policy lookup.

           The Postfix socketmap client expects TCP endpoint  names  of  the  form
           inet:host:port:name,  or  UNIX-domain  endpoints of the form unix:path-
           name:name.  In both cases, name specifies the name field in a socketmap
           client request (see "REQUEST FORMAT" below).

    PROTOCOL
           Socketmaps use a simple protocol: the client sends one request, and the
           server sends one reply.  Each request and each reply are  sent  as  one
           netstring object.

    REQUEST FORMAT
           The  socketmap  protocol supports only the lookup request.  The request
           has the following form:

           name <space> key
                  Search the named socketmap for the specified key.

           Postfix will not generate partial search  keys  such  as  domain  names
           without  one  or more subdomains, network addresses without one or more
           least-significant octets, or email  addresses  without  the  localpart,
           address  extension  or domain portion. This behavior is also found with
           cidr:, pcre:, and regexp: tables.

    REPLY FORMAT
           Replies must have the following form:

           OK <space> data
                  The requested data was found.

           NOTFOUND <space>
                  The requested data was not found.

           TEMP <space> reason

           TIMEOUT <space> reason

           PERM <space> reason
                  The request failed. The reason,  if  non-empty,  is  descriptive
                  text.

    PROTOCOL LIMITS
           The  Postfix  socketmap client requires that replies are no longer than
           100000 bytes (not including the netstring  encapsulation).  This  limit
           can  be changed with the socketmap_max_reply_size configuration parame-
           ter (Postfix 3.10 and later).

           The Postfix socketmap client enforces a 100s time limit to connect to a
           socketmap  server, to send a request, and to receive a reply. It closes
           an idle connection after 10s, and closes  an  active  connection  after
           100s. These limits are not (yet) configurable.

    SECURITY
           This  map  cannot  be  used for security-sensitive information, because
           neither the connection nor the server are authenticated.

    CONFIGURATION PARAMETERS
           socketmap_max_reply_size (100000)
                  The maximum allowed reply size  from  a  socketmap  server,  not
                  including the netstring encapsulation.

    SEE ALSO
           https://cr.yp.to/proto/netstrings.txt, netstring definition
           postconf(1), Postfix supported lookup tables
           postmap(1), Postfix lookup table manager
           regexp_table(5), format of regular expression tables
           pcre_table(5), format of PCRE tables
           cidr_table(5), format of CIDR tables

    README FILES
           DATABASE_README, Postfix lookup table overview

    BUGS
           The protocol time limits are not yet configurable.

    LICENSE
           The Secure Mailer license must be distributed with this software.

    HISTORY
           Socketmap support was introduced with Postfix version 2.10.

           The socketmap protocol was published with Sendmail v8.13.

    AUTHOR(S)
           Wietse Venema
           IBM T.J. Watson Research
           P.O. Box 704
           Yorktown Heights, NY 10598, USA

           Wietse Venema
           Google, Inc.
           111 8th Avenue
           New York, NY 10011, USA

           Wietse Venema
           porcupine.org

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