cidr_table(5) - Linux man page
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.
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:
- 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 recommended.
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.
Table Search Order
Patterns are applied in the order as specified in the table, until a pattern is found that matches the search string.
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
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
AUTHOR(S)
The CIDR table lookup code was originally written by: Jozsef Kadlecsik kadlec@blackhole.kfki.hu 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
