--- linux-2.4.20-gentoo-r7/net/ipv4/netfilter/ipt_realm.c.old	2003-10-19 12:55:59.000000000 +0100
+++ linux-2.4.20-gentoo-r7/net/ipv4/netfilter/ipt_realm.c	2003-10-19 13:08:20.000000000 +0100
@@ -26,6 +26,18 @@
     
     if((dst = skb->dst) == NULL)
          return 0;
+
+    #ifndef _NET_DST_H_have_tclassid
+	#warning Could not find _NET_DST_H_have_tclassid...
+	#warning 
+	#warning Make sure you have enabled the following
+	#warning in your configuration:-
+	#warning
+	#warning Network Options >> QoS and/or fair queuing
+	#warning >> Packet Classifier API 
+	#warning >> Routing table based classifier
+    #endif
+
     id = dst->tclassid;
 
     return (info->id == (id & info->mask)) ^ info->invert;
--- linux-2.4.20-gentoo-r7/include/net/dst.h.old	2003-10-19 12:54:13.000000000 +0100
+++ linux-2.4.20-gentoo-r7/include/net/dst.h	2003-10-19 13:04:01.000000000 +0100
@@ -58,6 +58,7 @@
 	int			(*output)(struct sk_buff*);
 
 #ifdef CONFIG_NET_CLS_ROUTE
+	#define _NET_DST_H_have_tclassid
 	__u32			tclassid;
 #endif