--- chan_sip.c.orig	2011-01-14 21:49:57.000000000 +0100
+++ chan_sip.c	2011-01-14 21:53:12.000000000 +0100
@@ -13774,12 +13774,19 @@
 	/*! \todo XXX here too we interpret a missing @domain as a name-only
 	 * URI, whereas the RFC says this is a domain-only uri.
 	 */
-	if (!ast_strlen_zero(domain) && !AST_LIST_EMPTY(&domain_list)) {
-		if (!check_sip_domain(domain, NULL, 0)) {
-			transmit_response(p, "404 Not found (unknown domain)", &p->initreq);
-			return AUTH_UNKNOWN_DOMAIN;
-		}
-	}
+        /* Strip off the domain name */
+        if ((c = strchr(name, '@'))) {
+                *c++ = '\0';
+                domain = c;
+                if ((c = strchr(domain, ':')))  /* Remove :port */
+                        *c = '\0';
+                if (!ast_strlen_zero(domain) && !AST_LIST_EMPTY(&domain_list)) {
+                       if (!check_sip_domain(domain, NULL, 0)) {
+                               transmit_response(p, "404 Not found (unknown domain)", &p->initreq);
+                               return AUTH_UNKNOWN_DOMAIN;
+                       }
+                }
+        }
 
 	ast_string_field_set(p, exten, name);
 	build_contact(p);