I get alot of neighbour solicitation packets with a non-255 hop limit. Those hosts are not close or related to me at all. The packets look like this: 16:51:36.630204 3ffe:b80:2:5cf3::2 > 2001:670:8e:f000::2: icmp6: neighbor sol: who has 2001:670:8e:f000::2 (len 24, hlim 249) 16:51:37.633349 3ffe:b80:2:5cf3::2 > 2001:670:8e:f000::2: icmp6: neighbor sol: who has 2001:670:8e:f000::2 (len 24, hlim 249) 16:51:38.619376 3ffe:b80:2:5cf3::2 > 2001:670:8e:f000::2: icmp6: neighbor sol: who has 2001:670:8e:f000::2 (len 24, hlim 249) If I understand this right, because it's send to an unicast address, it's trying to do a neighbour reachability test. Is sending that to me a correct solicitation? Isn't it supposed to be send to the neighbour's address? From what I understand it should be have been dropped because of 2 reasons: It's has a non-255 hop limit, and the target address is not assigned to the receiving interface. Anyway, this seems to be caused by FreeBSD (or *BSD) hosts, and I should probably take this up with them to find out what's causing it. We're currently assuming they set up a wrong prefix length. Anyway, because the hop limit is 255, this is a invalid solicitation. The problem I have is that 2001:670:8e:f000::2 gets this packet in the first place. It complains about this by sending this to my logs: ICMP NDISC: fake message with non-255 Hop Limit received: 249 The Linux box in front of it passes those packets and does not complain about it. Why not? It's running 2.4.17. Kurt - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
