Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 165796)
+++ channels/chan_sip.c	(working copy)
@@ -4821,7 +4821,7 @@
 		dialog->socket.type = SIP_TRANSPORT_UDP;
 	if (!dialog->socket.port)
 		dialog->socket.port = bindaddr.sin_port;
-	dialog->sa.sin_port = htons(portno);
+	dialog->sa.sin_port = htons(portno ? portno : STANDARD_SIP_PORT);
 	dialog->recv = dialog->sa;
 	return 0;
 }
@@ -6535,6 +6535,9 @@
 		p->ourip = internip;
 	else {
 		p->sa = *sin;
+		if (!p->sa.sin_port) {
+			p->sa.sin_port = htons(STANDARD_SIP_PORT);
+		}
 		ast_sip_ouraddrfor(&p->sa.sin_addr, &p->ourip);
 	}
 
@@ -8527,6 +8530,9 @@
 		p->ourip = internip;
 	else {
 		p->sa = *sin;
+		if (!p->sa.sin_port) {
+			p->sa.sin_port = STANDARD_SIP_PORT;
+		}
 		ast_sip_ouraddrfor(&p->sa.sin_addr, &p->ourip);
 	}
 
@@ -12515,7 +12521,7 @@
 		memset(&p->sa, 0, sizeof(p->sa));
 		p->sa.sin_family = AF_INET;
 		memcpy(&p->sa.sin_addr, hp->h_addr, sizeof(p->sa.sin_addr));
-		p->sa.sin_port = htons(pt ? atoi(pt) : STANDARD_SIP_PORT);
+		p->sa.sin_port = htons(pt && atoi(pt) ? atoi(pt) : STANDARD_SIP_PORT);
 
 		if (sip_debug_test_pvt(p)) {
 			const struct sockaddr_in *dst = sip_real_dst(p);