+ # Add source and destination interface to the filter rules.
+ # These are supposed to help filtering forged packets that originate
+ # from BLUE with an IP address from GREEN for instance.
+ if ($source_intf) {
+ push(@source_options, ("-i", $source_intf));
+ }
+
+ if ($destination_intf) {
+ push(@destination_options, ("-o", $destination_intf));
+ }
+