Index: sys/netinet/tcp_input.c
===================================================================
--- sys/netinet/tcp_input.c
+++ sys/netinet/tcp_input.c
@@ -139,7 +139,7 @@
     &VNET_NAME(tcp_delack_enabled), 0,
     "Delay ACK to try and piggyback it onto a data packet");
 
-VNET_DEFINE(int, drop_synfin) = 0;
+VNET_DEFINE(int, drop_synfin) = 1;
 #define	V_drop_synfin		VNET(drop_synfin)
 SYSCTL_INT(_net_inet_tcp, OID_AUTO, drop_synfin, CTLFLAG_VNET | CTLFLAG_RW,
     &VNET_NAME(drop_synfin), 0,