diff --git a/Shorewall/Perl/Shorewall/Tc.pm b/Shorewall/Perl/Shorewall/Tc.pm
index 8f530956c..c6c85bfaa 100644
--- a/Shorewall/Perl/Shorewall/Tc.pm
+++ b/Shorewall/Perl/Shorewall/Tc.pm
@@ -980,7 +980,7 @@ sub process_tc_filter() {
 
     ( $device , my $devref ) = dev_by_number( $device );
 
-    my $devnum = $devref->{number};
+    my $devnum = in_hex $devref->{number};
 
     my $tcref = $tcclasses{$device};