Normally, the relocated(5) table is specified as a text file that serves as input to the postmap(1) command. The result, an indexed file in dbm or db format, is used for fast searching by the mail system. Execute the command "postmap /etc/postfix/relocated" to rebuild an indexed file after changing the corresponding relocated table.
When the table is provided via other means such as NIS, LDAP or SQL, the same lookups are done as for ordinary indexed files.
Alternatively, the table can be provided as a regular-expression map where patterns are given as regular expressions, or lookups can be directed to TCP-based server. In those case, the lookups are done in a slightly different way as described below under "REGULAR EXPRESSION TABLES" or "TCP-BASED TABLES".
Table lookups are case insensitive.
The search string is folded to lowercase before database lookup. As of Postfix 2.3, the search string is not case folded with database types such as regexp: or pcre: whose lookup fields can match both upper and lower case.
The input format for the postmap(1) command is as follows:
Where new_location specifies contact information such as an email address, or perhaps a street address or telephone number.
With lookups from indexed files such as DB or DBM, or from networked tables such as NIS, LDAP or SQL, patterns are tried in the order as listed below:
When a mail address localpart contains the optional recipient delimiter (e.g., user+foo@domain), the lookup order becomes: user+foo@domain, user@domain, user+foo, user, and @domain.
This section describes how the table lookups change when the table is given in the form of regular expressions or when lookups are directed to a TCP-based server. For a description of regular expression lookup table syntax, see regexp_table(5) or pcre_table(5). For a description of the TCP client/server table lookup protocol, see tcp_table(5). This feature is not available up to and including Postfix version 2.4.
Each pattern is a regular expression that is applied to the entire address being looked up. Thus, user@domain mail addresses are not broken up into their user and @domain constituent parts, nor is user+foo broken up into user and foo.
Patterns are applied in the order as specified in the table, until a pattern is found that matches the search string.
Results are the same as with indexed file lookups, with the additional feature that parenthesized substrings from the pattern can be interpolated as $1, $2 and so on.
This section describes how the table lookups change when lookups are directed to a TCP-based server. For a description of the TCP client/server lookup protocol, see tcp_table(5). This feature is not available up to and including Postfix version 2.4.
Each lookup operation uses the entire address once. Thus, user@domain mail addresses are not broken up into their user and @domain constituent parts, nor is user+foo broken up into user and foo.
Results are the same as with indexed file lookups.
The following main.cf parameters are especially relevant. The text below provides only a parameter summary. See postconf(5) for more details including examples.
Other parameters of interest:
trivial-rewrite(8), address resolver postmap(1), Postfix lookup table manager postconf(5), configuration parameters
Use "postconf readme_directory" or "postconf html_directory" to locate this information.
DATABASE_README, Postfix lookup table overview ADDRESS_REWRITING_README, address rewriting guide
The Secure Mailer license must be distributed with this software.
Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA