diff -up ntp-4.2.6p5/ntpd/ntp_proto.c.sourceport ntp-4.2.6p5/ntpd/ntp_proto.c

--- ntp-4.2.6p5/ntpd/ntp_proto.c.sourceport	2015-02-06 16:43:27.857879763 +0100

+++ ntp-4.2.6p5/ntpd/ntp_proto.c	2015-02-06 16:43:56.446879712 +0100

@@ -334,7 +334,7 @@ receive(

 	 * reveals a clogging attack.

 	 */

 	sys_received++;

-	if (SRCPORT(&rbufp->recv_srcadr) < NTP_PORT) {

+	if (SRCPORT(&rbufp->recv_srcadr) == 0) {

 		sys_badlength++;

 		return;				/* bogus port */

 	}