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"
To test lookup tables, use the "postmap -q" command as described in the SYNOPSIS above.
The general form of a Postfix CIDR table is:
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
Note: address information may be enclosed inside "" but this form is not
IPv6 support is available in Postfix 2.2 and later.
When a search string matches the specified network address, use the corresponding
blank lines and comments
Empty lines and whitespace-only lines are ignored, as are lines whose first non-
whitespace character is a `#'.
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
smtpd_client_restrictions = ... cidr:/etc/postfix/client.cidr ...
# Rule order matters. Put more specific whitelist entries
# before more general blacklist entries.
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:
KFKI Research Institute for Particle and Nuclear Physics
1525 Budapest, Hungary
Adopted and adapted by:
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA