diff --git a/kamailio/nat-traversal-role.cfg b/kamailio/nat-traversal-role.cfg
index 1bc42eb..2a6d893 100644
--- a/kamailio/nat-traversal-role.cfg
+++ b/kamailio/nat-traversal-role.cfg
@@ -101,6 +101,10 @@ route[NAT_MANAGE]
         setbflag(FLB_NATB);
    }
 
+   if (is_reply()) {
+       set_contact_alias();
+   }
+
    if (!(isflagset(FLT_NATS) || isbflagset(FLB_NATB))) {
         xlog("L_DEBUG", "$ci|log|NOT SETTING\n");
         return;