diff --git a/etc/inc/filter.inc b/etc/inc/filter.inc
index 57be4ba5b1..b597651196 100644
--- a/etc/inc/filter.inc
+++ b/etc/inc/filter.inc
@@ -563,7 +563,7 @@ function filter_nat_rules_generate()
 	if (is_array($config['nat']['onetoone']))
 	foreach($config['nat']['onetoone'] as $one) {
 		if($one['useftphelper']) {
-			$int = convert_friendly_interface_to_real_interface_name($one['interface']);
+			$int = $FilterIflist[$one['interface']]['if'];
 			$external_address = $one['external'];
 			$internal_address = $one['internal'];
 			if($int && $external_address && $internal_address) {
@@ -2445,4 +2445,4 @@ EOD;
 	return($ipfrules);
 }
 
-?>
\ No newline at end of file
+?>