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  access control
       tables.  These tables are usually in  dbm  or  db  format.
       Alternatively,  access  control 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
       /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
       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)