Don't change interfaces unless there is something wrong with the old one.

This is NTP bug [2043] and this patch should be removed after upgrading to

a version of NTP with a fix for that bug.

--- ntpd/ntp_peer.c

+++ ntpd/ntp_peer.c

@@ -718,9 +718,13 @@

 	/*

 	 * this is called when the interface list has changed

 	 * give all peers a chance to find a better interface

+	 * but only if either they don't have an address already

+	 * or if the one they have hasn't worked for a while.

 	 */

-	for (p = peer_list; p != NULL; p = p->p_link)

-		peer_refresh_interface(p);

+	for (p = peer_list; p != NULL; p = p->p_link) {

+		if (!(p->dstadr && (p->reach & 0x3)))

+			peer_refresh_interface(p);

+	}

 }