CIDR format table in Postfix doesn't work.

  • Postfix supports CIDR tables but it is not required to run postmap command on /etc/postfix/network_table file. CIDR format is just a text format. It is not required to transform it to another format. To enable a CIDR table, create a file with the network enties which should be allowed or denied access to the mail server
  # cat /etc/postfix/network_table 
  # Rule order matters. Put more specific whitelist entries
  # before more general blacklist entries.
  127.0.0.0/8 OK
  10.0.0.0/24 OK
  192.168.0.0/24 OK
  172.16.0.0/24 REJECT
  • Add following lines in /etc/postfix/main.cf
   mynetworks = cidr:/etc/postfix/network_table
   smtpd_client_restrictions = cidr:/etc/postfix/network_tabl
  • Restart postfix service
  # service postfix restart
  • For more information on cidr_table consult the man page man cidr_table.

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