Postfix lookup table types

To find out what database types your Postfix system supports, use the "postconf -m" command. Here is a list of database types that are often supported:

btree

A sorted, balanced tree structure. This is available only on systems with support for Berkeley DB databases. Database files are created with the postmap(1) or postalias(1) command. The lookup table name as used in "btree:table" is the database file name without the ".db" suffix.

cdb

A read-optimized structure with no support for incremental updates. Database files are created with the postmap(1) or postalias(1) command. The lookup table name as used in "cdb:table" is the database file name without the ".cdb" suffix. This feature is available with Postfix 2.2 and later.

cidr

A table that associates values with Classless Inter-Domain Routing (CIDR) patterns. The table format is described in cidr_table(5).

dbm

An indexed file type based on hashing. This is available only on systems with support for DBM databases. Database files are created with the postmap(1) or postalias(1) command. The lookup table name as used in "dbm:table" is the database file name without the ".dir" or ".pag" suffix.

environ

The UNIX process environment array. The lookup key is the variable name. The lookup table name in "environ:table" is ignored.

hash

An indexed file type based on hashing. This is available only on systems with support for Berkeley DB databases. Database files are created with the postmap(1) or postalias(1) command. The database name as used in "hash:table" is the database file name without the ".db" suffix.

ldap (read-only)

Perform lookups using the LDAP protocol. Configuration details are given in the ldap_table(5).

mysql (read-only)

Perform MySQL database lookups. Configuration details are given in mysql_table(5).

netinfo (read-only)

Perform Netinfo database lookups.

nis (read-only)

Perform NIS database lookups.

nisplus (read-only)

Perform NIS+ database lookups. Configuration details are given in nisplus_table(5).

pcre (read-only)

A lookup table based on Perl Compatible Regular Expressions. The file format is described in pcre_table(5). The lookup table name as used in " pcre:table" is the name of the regular expression file.

pgsql (read-only)

Perform PostgreSQL database lookups. Configuration details are given in pgsql_table(5).

proxy (read-only)

Access information via the Postfix proxymap(8) service. The lookup table name syntax is " proxy: type:table".

regexp (read-only)

A lookup table based on regular expressions. The file format is described in regexp_table(5). The lookup table name as used in " regexp:table" is the name of the regular expression file.

sdbm

An indexed file type based on hashing. This is available only on systems with support for SDBM databases. Database files are created with the postmap(1) or postalias(1) command. The lookup table name as used in "sdbm:table" is the database file name without the ".dir" or ".pag" suffix.

static (read-only)

Always returns its lookup table name as lookup result. For example, the lookup table "static:foobar" always returns the string "foobar" as lookup result.

tcp

Access information through a TCP/IP server. The protocol is described in tcp_table(5). The lookup table name is " tcp:host:port" where "host" specifies a symbolic hostname or a numeric IP address, and "port" specifies a symbolic service name or a numeric port number. This protocol is not available up to and including Postfix version 2.2.

unix (read-only)

A limited way to query the UNIX authentication database. The following tables are implemented:

unix:passwd.byname

The table is the UNIX password database. The key is a login name. The result is a password file entry in passwd(5) format.

unix:group.byname

The table is the UNIX group database. The key is a group name. The result is a group file entry in group(5) format.

Other lookup table types may be available depending on how Postfix was built. With some Postfix distributions the list is dynamically extensible as support for lookup tables is dynamically linked into Postfix.