CIDR_TABLE(5)                                                    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.   Alterna-
       tively,  lookup tables can be specified in CIDR (Classless
       Inter-Domain Routing) form.

       To find out what types of lookup tables your Postfix  sys-
       tem 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 deci-
              mal 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. There-
              fore 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 logi-
              cal line.

TABLE SEARCH ORDER
       Patterns are applied in the order as specified in the  ta-
       ble,  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
       DATABASE_README, Postfix lookup table overview

AUTHOR(S)
       The CIDR table lookup code was originally written by:
       Jozsef Kadlecsik
       [email protected]
       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

                                                                 CIDR_TABLE(5)