diff --git a/src/etc/inc/interfaces.inc b/src/etc/inc/interfaces.inc
index e8f95c188..840352f27 100644
--- a/src/etc/inc/interfaces.inc
+++ b/src/etc/inc/interfaces.inc
@@ -3588,7 +3588,7 @@ function get_parent_interface($interface, $avoidrecurse = false)
     $parents = array();
 
     $realif = get_real_interface($interface);
-    if (does_interface_exist($realif)) {
+    if (!does_interface_exist($realif)) {
         return $parents;
     }