--- channels/chan_iax2.c.orig	2011-01-04 16:53:27.000000000 -0500
+++ channels/chan_iax2.c	2011-02-21 00:08:57.000000000 -0500
@@ -4555,7 +4555,7 @@
 			return -1;
 		}
 		ast_sockaddr_to_sin(&sin_tmp, sin);
-		sin->sin_port = htons(IAX_DEFAULT_PORTNO);
+		if (sin->sin_port == 0) sin->sin_port = htons(IAX_DEFAULT_PORTNO);
 		/* use global iax prefs for unknown peer/user */
 		/* But move the calling channel's native codec to the top of the preference list */
 		memcpy(&ourprefs, &prefs, sizeof(ourprefs));