cidr_table - format of Postfix CIDR tables
postmap -q "string" cidr:/etc/postfix/filename
postmap -q - cidr:/etc/postfix/filename <inputfile
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.
The general form of a Postfix CIDR table is:
network_address/network_mask result When a search string matches the specified network block, use the corresponding result 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 ":".
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.
network_address result When a search string matches the specified network address, use the corresponding result 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.
Patterns are applied in the order as specified in the table, until a pattern is found that matches the search string.
/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
postmap(1), Postfix lookup table manager regexp_table(5), format of regular expression tables pcre_table(5), format of PCRE tables
Use "postconf readme_directory" or "postconf html_directory" to locate this information.DATABASE_README, Postfix lookup table overview
CIDR table support was introduced with Postfix version 2.1.
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