diff --git a/Shorewall/Perl/Shorewall/Chains.pm b/Shorewall/Perl/Shorewall/Chains.pm
index e2bd02534..00a9f5165 100644
--- a/Shorewall/Perl/Shorewall/Chains.pm
+++ b/Shorewall/Perl/Shorewall/Chains.pm
@@ -116,6 +116,7 @@ our %EXPORT_TAGS = (
 				       blacklist_chain
 				       zone_forward_chain
 				       use_forward_chain
+				       filter_chain
 				       input_chain
 				       zone_input_chain
 				       use_input_chain
@@ -1617,6 +1618,14 @@ sub use_forward_chain($$) {
     $interfaceref->{options}{use_forward_chain} && keys %{ zone_interfaces( $zone ) } > 1;
 }
 
+#
+# Filter Chain for an interface
+#
+sub filter_chain($) {
+    my $interface = shift;
+    ( $config{USE_PHYSICAL_NAMES} ? chain_base( get_physical( $interface ) ) : $interface ) . '_flt';
+}
+
 #
 # Input Chain for an interface
 #