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

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

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.  

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.

/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

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

NAME

SYNOPSIS

DESCRIPTION

TABLE FORMAT

TABLE SEARCH ORDER

EXAMPLE SMTPD ACCESS MAP

SEE ALSO

README FILES

HISTORY

AUTHOR(S)