diff -urN linux-2.6.6/net/ipv6/route.c linux-2.6.6.pmtu/net/ipv6/route.c
--- linux-2.6.6/net/ipv6/route.c	2004-05-09 19:33:05.000000000 -0700
+++ linux-2.6.6.pmtu/net/ipv6/route.c	2004-05-26 13:15:28.288796272 -0700
@@ -554,6 +554,8 @@
 
 	if (mtu < dst_pmtu(dst) && rt6->rt6i_dst.plen == 128) {
 		rt6->rt6i_flags |= RTF_MODIFIED;
+		if (mtu < IPV6_MIN_MTU)
+			mtu = IPV6_MIN_MTU;
 		dst->metrics[RTAX_MTU-1] = mtu;
 	}
 }
diff -urN linux-2.6.6/net/ipv6/xfrm6_policy.c linux-2.6.6.pmtu/net/ipv6/xfrm6_policy.c
--- linux-2.6.6/net/ipv6/xfrm6_policy.c	2004-05-09 19:32:26.000000000 -0700
+++ linux-2.6.6.pmtu/net/ipv6/xfrm6_policy.c	2004-05-26 13:15:28.322791104 -0700
@@ -236,10 +236,10 @@
 {
 	struct dst_entry *path = dst->path;
 
-	if (mtu >= 1280 && mtu < dst_pmtu(dst))
-		return;
-
-	path->ops->update_pmtu(path, mtu);
+	if (mtu >= IPV6_MIN_MTU && mtu < dst_pmtu(dst))
+		path->ops->update_pmtu(path, mtu);
+	
+	return;
 }
 
 struct dst_ops xfrm6_dst_ops = {