diff --git a/Shorewall/Perl/Shorewall/Config.pm b/Shorewall/Perl/Shorewall/Config.pm
index c0c230b45..702336868 100644
--- a/Shorewall/Perl/Shorewall/Config.pm
+++ b/Shorewall/Perl/Shorewall/Config.pm
@@ -51,6 +51,7 @@ our @EXPORT = qw(
 		 progress_message_nocompress
 		 progress_message2
 		 progress_message3
+		 supplied
 		 read_action_param
 		 set_action_param
                 );
@@ -1299,6 +1300,15 @@ sub split_list1( $$ ) {
     @list2;
 }
 
+#
+# Determine if a value has been supplied
+#
+sub supplied( $ ) {
+    my $val = shift;
+
+    defined $val && $val ne '';
+}
+
 #
 # Pre-process a line from a configuration file.