diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
index 7e50c9ded6ac..fd88e69b25a2 100644
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -1543,7 +1543,6 @@ syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
 	sc->sc_todctx = todctx;
 #endif
 	sc->sc_irs = th->th_seq;
-	sc->sc_iss = arc4random();
 	sc->sc_flags = 0;
 	sc->sc_flowlabel = 0;
 
@@ -1617,6 +1616,8 @@ syncache_add(struct in_conninfo *inc, struct tcpopt *to, struct tcphdr *th,
 
 	if (V_tcp_syncookies)
 		sc->sc_iss = syncookie_generate(sch, sc);
+	else
+		sc->sc_iss = arc4random();
 #ifdef INET6
 	if (autoflowlabel) {
 		if (V_tcp_syncookies)