Index: sys/netinet/tcp_syncache.c
===================================================================
--- sys/netinet/tcp_syncache.c
+++ sys/netinet/tcp_syncache.c
@@ -1071,8 +1071,12 @@
 	/*
 	 * If timestamps were negotiated the reflected timestamp
 	 * must be equal to what we actually sent in the SYN|ACK.
+	 *
+	 * Some boxes send broken timestamp replies during the
+	 * SYN+ACK phase, ignore timestamps of 0.
 	 */
-	if ((to->to_flags & TOF_TS) && to->to_tsecr != sc->sc_ts) {
+	if ((to->to_flags & TOF_TS) && to->to_tsecr &&
+	    to->to_tsecr != sc->sc_ts) {
 		if ((s = tcp_log_addrs(inc, th, NULL, NULL)))
 			log(LOG_DEBUG, "%s; %s: TSECR %u != TS %u, "
 			    "segment rejected\n",