CIDR_TABLE(5)							File Formats Manual						     CIDR_TABLE(5)

NAME

       cidr_table - format of Postfix CIDR tables

SYNOPSIS

       postmap -q "string" cidr:/etc/postfix/filename

       postmap -q - cidr:/etc/postfix/filename <inputfile

DESCRIPTION

       The  Postfix  mail  system uses optional lookup tables.	These tables are usually in dbm or db format.  Alternatively, lookup tables can be
       specified 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 "postconf -m" command.

       To test lookup tables, use the "postmap -q" command as described in the SYNOPSIS above.

TABLE FORMAT

       The general form of a Postfix CIDR table is:

       pattern	   result
	      When  a  search  string  matches the specified pattern, use the corresponding result value. The pattern must be in network/prefix or
	      network_address form (see ADDRESS PATTERN SYNTAX below).

       !pattern     result
	      When a search string does not match the specified pattern, use the specified result value. The pattern must be in network/prefix	or
	      network_address form (see ADDRESS PATTERN SYNTAX below).

	      This feature is available in Postfix 3.2 and later.

       if pattern

       endif  When a search string matches the specified pattern, match that search string against the patterns between if and endif.  The pattern
	      must be in network/prefix or network_address form (see ADDRESS PATTERN SYNTAX below). The if..endif can nest.

	      Note: do not prepend whitespace to text between if..endif.

	      This feature is available in Postfix 3.2 and later.

       if !pattern

       endif  When a search string does not match the specified pattern, match that search string against the patterns between if and  endif.  The
	      pattern must be in network/prefix or network_address form (see ADDRESS PATTERN SYNTAX below). The if..endif can nest.

	      Note: do not prepend whitespace to text between if..endif.

	      This feature is available in Postfix 3.2 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 logical line.

TABLE SEARCH ORDER

       Patterns are applied in the order as specified in the table, until a pattern is found that matches the search string.

ADDRESS PATTERN SYNTAX

       Postfix	CIDR  tables  are  pattern-based.  A  pattern is either a network_address which requires an exact match, or a network_address/pre-
       fix_length where the prefix_length part specifies the length of the network_address prefix that must be matched (the other bits in the net-
       work_address part must be zero).

       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 ":" or "::", where the latter is short-hand for a sequence of one or more all-zero	octet  pairs.  The
       pattern 0.0.0.0/0 matches every IPv4 address, and ::/0 matches every IPv6 address.  IPv6 support is available in Postfix 2.2 and later.

       Before  comparisons  are  made, lookup keys and table entries are converted from string to binary. Therefore, IPv6 patterns will be matched
       regardless of leading zeros (a leading zero in an IPv4 address octet indicates octal notation).

       Note: address information may be enclosed inside "[]" but this form is not required.

EXAMPLE SMTPD ACCESS MAP

       /etc/postfix/main.cf:
	   smtpd_client_restrictions = ... cidr:/etc/postfix/client.cidr ...

       /etc/postfix/client.cidr:
	   # Rule order matters. Put more specific whitelist entries
	   # before more general blacklist entries.
	   192.168.1.1		   OK
	   192.168.0.0/16	   REJECT
	   2001:db8::1		   OK
	   2001:db8::/32	   REJECT

SEE ALSO

       postmap(1), Postfix lookup table manager
       regexp_table(5), format of regular expression tables
       pcre_table(5), format of PCRE tables

README FILES

       Use "postconf readme_directory" or "postconf html_directory" to locate this information.
       DATABASE_README, Postfix lookup table overview

HISTORY

       CIDR table support was introduced with Postfix version 2.1.

AUTHOR(S)
       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)