socketmap_table - Man Page

Postfix socketmap table lookup client


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


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:pathname:name. In both cases, name specifies the name field in a socketmap client request (see "Request Format" below).


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

The Postfix socketmap client requires that replies are not longer than 100000 characters (not including the netstring encapsulation). 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.


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

See Also, 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

Use "postconf readme_directory" or "postconf html_directory" to locate this information.

DATABASE_README, Postfix lookup table overview


The protocol limits are not yet configurable.


The Secure Mailer license must be distributed with this software.


Socketmap support was introduced with Postfix version 2.10.


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

Referenced By

postconf(1), postfix(1).