    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 or
           mail routing. These tables are usually in lmdb:, cdb:, hash:,  or  dbm:
           format.

           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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