diff --git a/firewall_types.c b/firewall_types.c
index d6c601a..3f3a74a 100644
--- a/firewall_types.c
+++ b/firewall_types.c
@@ -44,6 +44,12 @@ int compare_rule(struct Rule *a, struct Rule *b) {
         result = akpa_numcmp(a->port.start, b->port.start);
     }
 
+    if (result == 0) {
+        if ((a->port.end != NULL) || (b->port.end != NULL)) {
+            result = akpa_numcmp(*a->port.end, *b->port.end);
+        }
+    }
+
     return result;
 }