diff --git a/sys/netinet/tcp_syncache.c b/sys/netinet/tcp_syncache.c
--- a/sys/netinet/tcp_syncache.c
+++ b/sys/netinet/tcp_syncache.c
@@ -200,6 +200,8 @@
 #define SYNCACHE_HASH6(inc, mask)					\
 	((tcp_syncache.hash_secret ^					\
 	  (inc)->inc6_faddr.s6_addr32[0] ^				\
+	  (inc)->inc6_faddr.s6_addr32[1] ^				\
+	  (inc)->inc6_faddr.s6_addr32[2] ^				\
 	  (inc)->inc6_faddr.s6_addr32[3] ^				\
 	  (inc)->inc_fport ^ (inc)->inc_lport) & mask)