Unofficial FreeBSD patch to drop all TCP packets with a sequence and/or acknowledgement number of 0.
bddfb3e361bb24d9627c76791fcc131730673d50ed341fc805e404d50e389e7f
--- tcp_input.c.orig Wed Feb 23 00:45:47 2000
+++ tcp_input.c Wed Feb 23 00:55:32 2000
@@ -482,2 +482,11 @@
+ /*
+ * Drop all packets with a sequence or acknowledgment number of
+ * zero if the RST flag isn't set.
+ * Omachonu Ogali <oogali@intranova.net>
+ *
+ */
+ if ((!(thflags & TH_RST)) && (((th_seq == 0) || (th_ack == 0)) || ((th_seq == 0) && (th_ack == 0)))) {
+ goto drop;
+
#ifdef TCP_DROP_SYNFIN