CIDR_TABLE(5)                                       CIDR_TABLE(5)

NAME
       cidr_table - format of Postfix CIDR tables

SYNOPSIS
       postmap -q "string" cidr:/usr/local/etc/postfix/filename

       postmap -q - cidr:/usr/local/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  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 address.

       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.

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
       /usr/local/etc/postfix/main.cf:
           smtpd_client_restrictions = ... cidr:/usr/local/etc/postfix/client.cidr ...

       /usr/local/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
       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

                                                    CIDR_TABLE(5)