diff -Nru linux-2.4.20/net/ipv4/netfilter/ipt_multiport.c linux-2.4.20-pom2patch/net/ipv4/netfilter/ipt_multiport.c
--- linux-2.4.20/net/ipv4/netfilter/ipt_multiport.c	2001-09-30 14:26:08.000000000 -0500
+++ linux-2.4.20-pom2patch/net/ipv4/netfilter/ipt_multiport.c	2003-05-02 13:01:12.000000000 -0500
@@ -78,7 +78,7 @@
 
 	/* Must specify proto == TCP/UDP, no unknown flags or bad count */
 	return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP)
-		&& !(ip->flags & IPT_INV_PROTO)
+		&& !(ip->invflags & IPT_INV_PROTO)
 		&& matchsize == IPT_ALIGN(sizeof(struct ipt_multiport))
 		&& (multiinfo->flags == IPT_MULTIPORT_SOURCE
 		    || multiinfo->flags == IPT_MULTIPORT_DESTINATION
