diff -ur linux.current/net/ipv4/netfilter/ipt_multiport.c linux-mine/net/ipv4/netfilter/ipt_multiport.c
--- linux-2.4.19-rc1/net/ipv4/netfilter/ipt_multiport.c	Tue Jun 20 23:32:27 2000
+++ linux/net/ipv4/netfilter/ipt_multiport.c	Tue Jul  9 10:43:23 2002
@@ -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