Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 213789)
+++ channels/chan_sip.c	(working copy)
@@ -7425,6 +7425,14 @@
 	 */
 	AST_NONSTANDARD_RAW_ARGS(host3, host2.hostpart, ':');
 
+	if (ast_strlen_zero(host2.extension))
+        {
+		ast_log(LOG_NOTICE, "Extension for '%s' not declared.  Setting to default 's' extension\n", host3.host);
+
+                host2.extension = "s";
+        }
+
+
 	/*!
 	 * user2.userpart => [peer?][transport://]user
 	 * user2.domain => domain (regdomain)