REGEXP_TABLE(5) REGEXP_TABLE(5) NAME regexp_table - format of Postfix regular expression tables SYNOPSIS regexp:/etc/postfix/filename DESCRIPTION The Postfix mail system uses optional tables for address rewriting or mail routing. These tables are usually in dbm or db format. Alternatively, lookup tables can be speci- fied in POSIX regular expression form. To find out what types of lookup tables your Postfix sys- tem supports use the postconf -m command. The general form of a Postfix regular expression table is: blanks and comments Blank lines are ignored, as are lines beginning with `#'. leading whitespace Lines that begin with whitespace continue the pre- vious line. pattern result When pattern matches a search string, use the cor- responding result. A line that starts with white space continues the preceding line. pattern1!pattern2 result Matches pattern1 but not pattern2. Each pattern is a regular expression enclosed by a pair of delimiters. The regular expression syntax is described in re_format(7). The expression delimiter can be any charac- ter, except whitespace or characters that have special meaning (traditionally the forward slash is used). The regular expression can contain whitespace. By default, matching is case-insensitive, although follow- ing the second slash with an `i' flag will reverse this. Other flags are `x' (disable extended expression syntax), and `m' (enable multi-line mode). Each pattern is applied to the entire lookup key string. Depending on the application, that string is an entire client hostname, an entire client IP address, or an entire mail address. Thus, no parent domain or parent network search is done, and 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 1 REGEXP_TABLE(5) REGEXP_TABLE(5) table, until a pattern is found that matches the search string. Substitution of substrings from the matched expression into the result string is possible using $1, $2, etc.. The macros in the result string may need to be written as ${n} or $(n) if they aren't followed by whitespace. EXAMPLES # Disallow sender-specified routing. This is a must if you relay mail # for other domains. /[%!@].*[%!@]/ 550 Sender-specified routing rejected # Postmaster is OK, that way they can talk to us about how to fix # their problem. /^postmaster@.*$/ OK # Protect your outgoing majordomo exploders /^(.*)-outgoing@(.*)$/!/^owner-.*/ 550 Use ${1}@${2} instead SEE ALSO pcre_table(5) format of PCRE tables AUTHOR(S) The regexp table lookup code was originally written by: LaMont Jones lamont@hp.com That code was based on the PCRE dictionary contributed by: Andrew McNamara andrewm@connect.com.au connect.com.au Pty. Ltd. Level 3, 213 Miller St North Sydney, NSW, Australia Adopted and adapted by: Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA 2