diff --git a/src/etc/inc/filter.inc b/src/etc/inc/filter.inc
index 2e3ce9835..0b066758e 100644
--- a/src/etc/inc/filter.inc
+++ b/src/etc/inc/filter.inc
@@ -570,26 +570,7 @@ function filter_generate_scrubing(&$FilterIflist)
 
     $scrubrules = '';
 
-    /* scrub per interface options */
-    if (empty($config['system']['scrub_interface_disable'])) {
-        foreach ($FilterIflist as $scrubif => $scrubcfg) {
-            if (isset($scrubcfg['virtual']) || empty($scrubcfg['descr'])) {
-                continue;
-            } else {
-                /* set up MSS clamping */
-                if (!empty($scrubcfg['mss']) && is_numeric($scrubcfg['mss']) &&
-                    !in_array($scrubcfg['if'], array('pppoe', 'pptp', 'l2tp'))) {
-                    $mssclamp = "max-mss " . (intval($scrubcfg['mss'] - 40));
-                } else {
-                    $mssclamp = '';
-                }
-                $scrubnodf = !empty($config['system']['scrubnodf']) ? "no-df" : "";
-                $scrubrnid = !empty($config['system']['scrubrnid']) ? "random-id" : "";
-                $scrubrules .= "scrub on \${$scrubcfg['descr']} all {$scrubnodf} {$scrubrnid} {$mssclamp}\n";
-            }
-        }
-    }
-
+    /* custom rules must be first */
     if (!empty($config['filter']['scrub']['rule'])) {
         foreach ($config['filter']['scrub']['rule'] as $scrub_rule) {
             if (!isset($scrub_rule['disabled'])) {
@@ -634,6 +615,26 @@ function filter_generate_scrubing(&$FilterIflist)
         }
     }
 
+    /* scrub per interface options */
+    if (empty($config['system']['scrub_interface_disable'])) {
+        foreach ($FilterIflist as $scrubif => $scrubcfg) {
+            if (isset($scrubcfg['virtual']) || empty($scrubcfg['descr'])) {
+                continue;
+            } else {
+                /* set up MSS clamping */
+                if (!empty($scrubcfg['mss']) && is_numeric($scrubcfg['mss']) &&
+                    !in_array($scrubcfg['if'], array('pppoe', 'pptp', 'l2tp'))) {
+                    $mssclamp = "max-mss " . (intval($scrubcfg['mss'] - 40));
+                } else {
+                    $mssclamp = '';
+                }
+                $scrubnodf = !empty($config['system']['scrubnodf']) ? "no-df" : "";
+                $scrubrnid = !empty($config['system']['scrubrnid']) ? "random-id" : "";
+                $scrubrules .= "scrub on \${$scrubcfg['descr']} all {$scrubnodf} {$scrubrnid} {$mssclamp}\n";
+            }
+        }
+    }
+
     return $scrubrules;
 }