Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 112128)
+++ channels/chan_sip.c	(working copy)
@@ -2539,7 +2539,7 @@
 			 * is because we only have the IP address and the host field might be
 			 * set as a name (and the reverse PTR might not match).
 			 */
-			if (var) {
+			if (var && sin) {
 				for (tmp = var; tmp; tmp = tmp->next) {
 					if (!strcasecmp(tmp->name, "host")) {
 						struct hostent *hp;