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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>postmap -q "</b><i>string</i><b>" <a href="regexp_table.5.html">regexp</a>:/etc/postfix/</b><i>filename</i>
<b>postmap -q - <a href="regexp_table.5.html">regexp</a>:/etc/postfix/</b><i>filename</i> <<i>inputfile</i>
<b>DESCRIPTION</b>
The Postfix mail system uses optional tables for address
rewriting, mail routing, or access control. These tables
are usually in <b>dbm</b> or <b>db</b> format.
Alternatively, lookup tables can be specified in POSIX
regular expression form. In this case, each input is com-
pared against a list of patterns. When a match is found,
the corresponding result is returned and the search is
terminated.
To find out what types of lookup tables your Postfix sys-
tem supports use the "<b>postconf -m</b>" command.
To test lookup tables, use the "<b>postmap -q</b>" command as
described in the SYNOPSIS above.
<b>COMPATIBILITY</b>
With Postfix version 2.2 and earlier specify "<b>postmap -fq</b>"
to query a table that contains case sensitive patterns.
Patterns are case insensitive by default.
<b>TABLE FORMAT</b>
The general form of a Postfix regular expression table is:
<b>/</b><i>pattern</i><b>/</b><i>flags result</i>
When <i>pattern</i> matches the input string, use the cor-
responding <i>result</i> value.
<b>!/</b><i>pattern</i><b>/</b><i>flags result</i>
When <i>pattern</i> does <b>not</b> match the input string, use
the corresponding <i>result</i> value.
<b>if /</b><i>pattern</i><b>/</b><i>flags</i>
<b>endif</b> Match the input string against the patterns between
<b>if</b> and <b>endif</b>, if and only if that same input string
also matches <i>pattern</i>. The <b>if</b>..<b>endif</b> can nest.
Note: do not prepend whitespace to patterns inside
<b>if</b>..<b>endif</b>.
This feature is available in Postfix 2.1 and later.
<b>if !/</b><i>pattern</i><b>/</b><i>flags</i>
<b>endif</b> Match the input string against the patterns between
<b>if</b> and <b>endif</b>, if and only if that same input string
does <b>not</b> match <i>pattern</i>. The <b>if</b>..<b>endif</b> can nest.
Note: do not prepend whitespace to patterns inside
<b>if</b>..<b>endif</b>.
This feature is available in Postfix 2.1 and later.
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.
Each pattern is a POSIX regular expression enclosed by a
pair of delimiters. The regular expression syntax is docu-
mented in <b>re_format</b>(7) with 4.4BSD, in <b>regex</b>(5) with
Solaris, and in <b>regex</b>(7) with Linux. Other systems may use
other document names.
The expression delimiter can be any character, except
whitespace or characters that have special meaning (tradi-
tionally the forward slash is used). The regular expres-
sion can contain whitespace.
By default, matching is case-insensitive, and newlines are
not treated as special characters. The behavior is con-
trolled by flags, which are toggled by appending one or
more of the following characters after the pattern:
<b>i</b> (default: on)
Toggles the case sensitivity flag. By default,
matching is case insensitive.
<b>m</b> (default: off)
Toggle the multi-line mode flag. When this flag is
on, the <b>^</b> and <b>$</b> metacharacters match immediately
after and immediately before a newline character,
respectively, in addition to matching at the start
and end of the input string.
<b>x</b> (default: on)
Toggles the extended expression syntax flag. By
default, support for extended expression syntax is
enabled.
<b>TABLE SEARCH ORDER</b>
Patterns are applied in the order as specified in the ta-
ble, until a pattern is found that matches the input
string.
Each pattern is applied to the entire input 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>.
<b>TEXT SUBSTITUTION</b>
Substitution of substrings from the matched expression
into the result string is possible using $1, $2, etc.;
specify $$ to produce a $ character as output. The macros
in the result string may need to be written as ${n} or
$(n) if they aren't followed by whitespace.
Note: since negated patterns (those preceded by <b>!</b>) return
a result when the expression does not match, substitutions
are not available for negated patterns.
<b>EXAMPLE SMTPD ACCESS MAP</b>
# Disallow sender-specified routing. This is a must if you relay mail
# for other domains.
/[%!@].*[%!@]/ 550 Sender-specified routing rejected
# Postmaster is OK, that way they can talk to us about how to fix
# their problem.
/^postmaster@/ OK
# Protect your outgoing majordomo exploders
if !/^owner-/
/^(.*)-outgoing@(.*)$/ 550 Use ${1}@${2} instead
endif
<b>EXAMPLE HEADER FILTER MAP</b>
# These were once common in junk mail.
/^Subject: make money fast/ REJECT
/^To: friend@public\.com/ REJECT
<b>EXAMPLE BODY FILTER MAP</b>
# First skip over base 64 encoded text to save CPU cycles.
~^[[:alnum:]+/]{60,}$~ OK
# Put your own body patterns here.
<b>SEE ALSO</b>
<a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
<a href="pcre_table.5.html">pcre_table(5)</a>, format of PCRE tables
<a href="cidr_table.5.html">cidr_table(5)</a>, format of CIDR tables
<b>README FILES</b>
<a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
<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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