<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html> <head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<title> Postfix manual - cidr_table(5) </title>
</head> <body> <pre>
CIDR_TABLE(5) CIDR_TABLE(5)
<b>NAME</b>
cidr_table - format of Postfix CIDR tables
<b>SYNOPSIS</b>
<b>postmap -q "</b><i>string</i><b>" <a href="cidr_table.5.html">cidr</a>:/etc/postfix/</b><i>filename</i>
<b>postmap -q - <a href="cidr_table.5.html">cidr</a>:/etc/postfix/</b><i>filename</i> <<i>inputfile</i>
<b>DESCRIPTION</b>
The Postfix mail system uses optional lookup tables. These tables are
usually in <b>dbm</b> or <b>db</b> format. Alternatively, lookup tables can be spec-
ified in CIDR (Classless Inter-Domain Routing) form. In this case, each
input is compared 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 system 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>TABLE FORMAT</b>
The general form of a Postfix CIDR table is:
<i>network</i><b>_</b><i>address</i><b>/</b><i>network</i><b>_</b><i>mask result</i>
When a search string matches the specified network block, use
the corresponding <i>result</i> value. Specify 0.0.0.0/0 to match every
IPv4 address, and ::/0 to match every IPv6 address.
An IPv4 network address is a sequence of four decimal octets
separated by ".", and an IPv6 network address is a sequence of
three to eight hexadecimal octet pairs separated by ":".
The <i>network</i><b>_</b><i>mask</i> is the number of high-order bits in the <i>net-</i>
<i>work</i><b>_</b><i>address</i> that the search string must match.
Before comparisons are made, lookup keys and table entries are
converted from string to binary. Therefore table entries will be
matched regardless of redundant zero characters.
Note: address information may be enclosed inside "[]" but this
form is not required.
IPv6 support is available in Postfix 2.2 and later.
<i>network</i><b>_</b><i>address result</i>
When a search string matches the specified network address, 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 logical line.
<b>TABLE SEARCH ORDER</b>
Patterns are applied in the order as specified in the table, until a
pattern is found that matches the search string.
<b>EXAMPLE SMTPD ACCESS MAP</b>
/etc/postfix/<a href="postconf.5.html">main.cf</a>:
<a href="postconf.5.html#smtpd_client_restrictions">smtpd_client_restrictions</a> = ... <a href="cidr_table.5.html">cidr</a>:/etc/postfix/client.cidr ...
/etc/postfix/client.<a href="cidr_table.5.html">cidr</a>:
# Rule order matters. Put more specific whitelist entries
# before more general blacklist entries.
192.168.1.1 OK
192.168.0.0/16 REJECT
<b>SEE ALSO</b>
<a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
<a href="regexp_table.5.html">regexp_table(5)</a>, format of regular expression tables
<a href="pcre_table.5.html">pcre_table(5)</a>, format of PCRE tables
<b>README FILES</b>
<a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
<b>HISTORY</b>
CIDR table support was introduced with Postfix version 2.1.
<b>AUTHOR(S)</b>
The CIDR table lookup code was originally written by:
Jozsef Kadlecsik
KFKI Research Institute for Particle and Nuclear Physics
POB. 49
1525 Budapest, Hungary
Adopted and adapted by:
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
Wietse Venema
Google, Inc.
111 8th Avenue
New York, NY 10011, USA
CIDR_TABLE(5)
</pre> </body> </html>