---
name: "socketmap_table"
section: "5"
platform: "macos"
package: "postfix"
version: "1636"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/socketmap_table"
---

# socketmap\_table(5)

Postfix socketmap table lookup client

## 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:***pathname***:***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 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.

## SECURITY

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

## SEE ALSO

```
http://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

```

```

Use "**postconf readme\_directory**" or "**postconf html\_directory**" to locate this information.

```
DATABASE_README, Postfix lookup table overview
```

## BUGS

The protocol 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.

## 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
```