NetBSD/gnu/dist/postfix/html/regexp_table.5.html

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REGEXP_TABLE(5) REGEXP_TABLE(5)
<b>NAME</b>
regexp_table - format of Postfix regular expression tables
<b>SYNOPSIS</b>
regexp:/etc/postfix/filename
<b>DESCRIPTION</b>
The Postfix mail system uses optional tables for address
rewriting or mail routing. These tables are usually in <b>dbm</b>
or <b>db</b> 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 <b>postconf</b> <b>-m</b> 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.
<i>pattern</i> <i>result</i>
When <i>pattern</i> matches a search string, use the cor-
responding <i>result</i>. A line that starts with white
space continues the preceding line.
<i>pattern1!pattern2</i> <i>result</i>
Matches <i>pattern1</i> but not <i>pattern2</i>.
Each pattern is a regular expression enclosed by a pair of
delimiters. The regular expression syntax is described in
<i>re_format</i>(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 <i>user@domain</i> mail addresses are not
broken up into their <i>user</i> and <i>domain</i> constituent parts,
nor is <i>user+foo</i> broken up into <i>user</i> and <i>foo</i>.
Patterns are applied in the order as specified in the
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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 $(n) if they aren't followed by whitespace.
<b>EXAMPLES</b>
# Disallow sender-specified routing. This is a must if you relay mail
# for other domains.
/[%!@].*[%!@]/ 550 Sender-specified routing rejected
# Postmaster is OK, that way they can talk to us about how to fix
# their problem.
/^postmaster@.*$/ OK
# Protect your outgoing majordomo exploders
/^(.*)-outgoing@(.*)$/!/^owner-.*/ 550 Use ${1}@${2} instead
<b>SEE</b> <b>ALSO</b>
<a href="pcre_table.5.html">pcre_table(5)</a> format of PCRE tables
<b>AUTHOR(S)</b>
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
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