diff -ur orig/ipvs/ip_vs.h ipvs/ip_vs.h
--- orig/ipvs/ip_vs.h	Wed Jan 10 07:42:53 2001
+++ ipvs/ip_vs.h	Sat Jan 20 20:18:02 2001
@@ -95,6 +95,7 @@
 #define IP_VS_CONN_F_IN_SEQ           0x0400    /* must do input seq adjust */
 #define IP_VS_CONN_F_NO_CPORT         0x0800    /* no client port set yet */
 
+#define NFMARK_IPVS_PROPERTY		-0x100
 
 #ifdef __KERNEL__
 
diff -ur orig/ipvs/ip_vs_conn.c ipvs/ip_vs_conn.c
--- orig/ipvs/ip_vs_conn.c	Mon Jan 15 13:43:46 2001
+++ ipvs/ip_vs_conn.c	Sat Jan 20 17:56:52 2001
@@ -645,6 +645,7 @@
 #ifdef CONFIG_NETFILTER_DEBUG
         skb->nf_debug = 1 << NF_IP_LOCAL_OUT;
 #endif /* CONFIG_NETFILTER_DEBUG */
+	skb->nfmark = NFMARK_IPVS_PROPERTY;
         ip_send(skb);
 
         LeaveFunction(10);
@@ -835,6 +836,7 @@
 #ifdef CONFIG_NETFILTER_DEBUG
         skb->nf_debug = 1 << NF_IP_LOCAL_OUT;
 #endif /* CONFIG_NETFILTER_DEBUG */
+	skb->nfmark = NFMARK_IPVS_PROPERTY;
         ip_send(skb);
 
         LeaveFunction(10);
@@ -972,6 +974,7 @@
 #ifdef CONFIG_NETFILTER_DEBUG
         skb->nf_debug = 1 << NF_IP_LOCAL_OUT;
 #endif /* CONFIG_NETFILTER_DEBUG */
+	skb->nfmark = NFMARK_IPVS_PROPERTY;
 	ip_send(skb);
 
         LeaveFunction(10);
@@ -1033,6 +1036,7 @@
 #ifdef CONFIG_NETFILTER_DEBUG
         skb->nf_debug = 1 << NF_IP_LOCAL_OUT;
 #endif /* CONFIG_NETFILTER_DEBUG */
+	skb->nfmark = NFMARK_IPVS_PROPERTY;
         ip_send(skb);
 
 #if 0000
diff -ur orig/ipvs/ip_vs_core.c ipvs/ip_vs_core.c
--- orig/ipvs/ip_vs_core.c	Wed Jan 10 07:42:53 2001
+++ ipvs/ip_vs_core.c	Sun Jan 21 14:00:36 2001
@@ -498,6 +498,20 @@
 	return NF_STOLEN;
 }
 
+static unsigned int ip_vs_post_routing(unsigned int hooknum,
+                              struct sk_buff **skb_p,
+                              const struct net_device *in,
+                              const struct net_device *out,
+                              int (*okfn)(struct sk_buff *))
+{
+struct sk_buff  *skb = *skb_p;
+
+	if (skb->nfmark != NFMARK_IPVS_PROPERTY) return NF_ACCEPT;
+
+	/* The packet was sent from IPVS, exit this chain */
+	(*okfn)(skb);
+	return NF_STOLEN;
+}
 
 /*
  *	Handle ICMP messages in the inside-to-outside direction (outgoing).
@@ -594,6 +608,8 @@
 		  NIPQUAD(ciph->saddr), ntohs(pptr[0]),
 		  NIPQUAD(ciph->daddr), ntohs(pptr[1]));
 
+	skb->nfmark = NFMARK_IPVS_PROPERTY;
+
 	return NF_ACCEPT;
 }
 
@@ -610,22 +626,21 @@
                               int (*okfn)(struct sk_buff *))
 {
 	struct sk_buff  *skb = *skb_p;
-	struct iphdr	*iph = skb->nh.iph;
+	struct iphdr	*iph;
 	union ip_vs_tphdr h;
 	struct ip_vs_conn *cp;
-	int size;
-
+	int size, doff, csum, csum_ok;
 	/*
 	 * 	doff holds transport protocol data offset
 	 *	csum holds its checksum
 	 *	csum_ok says if csum is valid
 	 */
-	int doff = 0;
-	int csum = 0;
-	int csum_ok = 0;
+
+	if (skb->nfmark == NFMARK_IPVS_PROPERTY) return NF_ACCEPT;
 
 	EnterFunction(11);
 
+	iph = skb->nh.iph;
 	h.raw = (char*) iph + iph->ihl * 4;
 	size = ntohs(iph->tot_len) - (iph->ihl * 4);
 	doff = ip_vs_proto_doff(iph->protocol, h.raw, size);
@@ -676,6 +691,9 @@
         }
 
         /* Check if the checksum is OK, when it is not UDP or check!=0 */
+	csum = 0;
+	csum_ok = 0;
+
         if ((iph->protocol != IPPROTO_UDP) || (h.uh->check != 0)) {
                 switch (skb->ip_summed)
                 {
@@ -782,6 +800,8 @@
 	ip_vs_set_state(cp, VS_STATE_OUTPUT, iph, h.portp);
 	ip_vs_conn_put(cp);
         
+	skb->nfmark = NFMARK_IPVS_PROPERTY;
+
         LeaveFunction(11);
 	return NF_ACCEPT;
 }
@@ -959,7 +979,7 @@
 	union ip_vs_tphdr h;
 	struct ip_vs_conn *cp;
 	unsigned short size;
-	int doff = 0;
+	int doff;
 	struct ip_vs_service *svc;
 
 	/*
@@ -1084,6 +1104,12 @@
         ip_vs_out, PF_INET, /* NF_IP_POST_ROUTING */NF_IP_FORWARD, 100
 };
 
+/* Before the netfilter NAT code, exit from POST_ROUTING */
+static struct nf_hook_ops ip_vs_post_routing_ops = {
+        { NULL, NULL },
+        ip_vs_post_routing, PF_INET, NF_IP_POST_ROUTING, NF_IP_PRI_NAT_SRC-1
+};
+
 
 /*
  *	Initialize IP Virtual Server
@@ -1122,10 +1148,17 @@
 		IP_VS_ERR("can't register out hook.\n");
 		goto cleanup_inops;
 	}
+	ret = nf_register_hook(&ip_vs_post_routing_ops);
+	if (ret < 0) {
+		IP_VS_ERR("can't register post_routing hook.\n");
+		goto cleanup_outops;
+	}
 
         IP_VS_INFO("ipvs loaded.\n");
 	return ret;
 
+  cleanup_outops:
+	nf_unregister_hook(&ip_vs_out_ops);
   cleanup_inops:
 	nf_unregister_hook(&ip_vs_in_ops);
   cleanup_app:
@@ -1141,6 +1174,7 @@
 
 static void __exit ip_vs_cleanup(void)
 {
+	nf_unregister_hook(&ip_vs_post_routing_ops);
 	nf_unregister_hook(&ip_vs_out_ops);
 	nf_unregister_hook(&ip_vs_in_ops);
 	ip_vs_app_cleanup();