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REGEXP_TABLE(5) REGEXP_TABLE(5)
<b>NAME</b>
regexp_table - format of Postfix regular expression tables
<b>SYNOPSIS</b>
<b>regexp:/etc/postfix/</b><i>filename</i>
<b>postmap</b> <b>-q</b> <b>"</b><i>string</i><b>"</b> <b>regexp:/etc/postfix/</b><i>filename</i>
<b>postmap</b> <b>-q</b> <b>-</b> <b>regexp:/etc/postfix/</b><i>filename</i> <<i>inputfile</i>
<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.
To test lookup tables, use the <b>postmap</b> command as
described in the SYNOPSIS above.
The general form of a Postfix regular expression table is:
<b>/</b><i>pattern</i><b>/</b><i>flags</i> <i>result</i>
<b>!/</b><i>pattern</i><b>/</b><i>flags</i> <i>result</i>
When <i>pattern</i> matches (does not match) a search
string, use the corresponding <i>result</i> value.
blank lines and comments
Empty lines and whitespace-only lines are ignored,
as are lines whose first non-whitespace character
is a `#'.
multi-line text
A logical line starts with non-whitespace text. A
line that starts with whitespace continues a logi-
cal line.
<b>if</b> <b>/</b><i>pattern</i><b>/</b><i>flags</i>
<b>if</b> <b>!/</b><i>pattern</i><b>/</b><i>flags</i>
<b>endif</b> Examine the lines between <b>if</b>..<b>endif</b> only if <i>pattern</i>
matches (does not match). The <b>if</b>..<b>endif</b> can nest.
Do not prepend whitespace to patterns inside
<b>if</b>..<b>endif</b>.
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, that is, treat newline
characters as special).
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
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 $(n) if they aren't followed by whitespace.
<b>EXAMPLE</b> <b>SMTPD</b> <b>ACCESS</b> <b>MAP</b>
# Disallow sender-specified routing. This is a must if you relay mail
# for other domains.
/[%!@].*[%!@]/ 550 Sender-specified routing rejected
# Postmaster is OK, that way they can talk to us about how to fix
# their problem.
/^postmaster@/ OK
# Protect your outgoing majordomo exploders
if !/^owner-/
/^(.*)-outgoing@(.*)$/ 550 Use ${1}@${2} instead
endif
<b>EXAMPLE</b> <b>HEADER</b> <b>FILTER</b> <b>MAP</b>
# These were once common in junk mail.
/^Subject: make money fast/ REJECT
/^To: friend@public\.com/ REJECT
<b>EXAMPLE</b> <b>BODY</b> <b>FILTER</b> <b>MAP</b>
# First skip over base 64 encoded text to save CPU cycles.
~^[[:alnum:]+/]{60,}$~ OK
# Put your own body patterns here.
<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
REGEXP_TABLE(5)
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