Third-party-based filters

In addition to local and FortiGuard filters, FortiOS can leverage third-party sources, which are known as DNS-based blackhole lists (DNSBL) or Open Relay Behavior-modification Systems (ORBS). These are maintained lists of IP addresses that have been identified as associated with spamming.

The following example demonstrates how to configure a DNSBL. The config emailfilter dnsbl command is used to configure either DNSBL or ORBS.

To configure a DNSBL:

1. Define the server to get the DNSBL list from:

   config emailfilter dnsbl
       edit 100
           set name "dnsbl"
           config entries
               edit 1
                   set status enable
                   set server <IP address or server name>
                   set action {reject | spam}
               next
           end
       next
   end

2. Add the DNSBL list to an email filter profile:

   config emailfilter profile
       edit "email_filter_profile"
           set options spamrbl
           set spam-rbl-table 100
       next
   end