diff --git a/sip.conf b/sip.conf
index 96f17e3..124d963 100644
--- a/sip.conf
+++ b/sip.conf
@@ -1632,3 +1632,4 @@ direct-media=no
 canrewrite=no
 dtmfmode=rfc2833
 insecure=invite,port
+qualify=yes