On 2014-12-22 15:45, Song Li wrote: > 在 2014/12/22 22:26, Nick Hilliard 写道: >> On 22/12/2014 13:50, Jeroen Massar wrote: >>> IXs themselves do not have ASNs, as they are Layer 2 providers. >> >> most modern IXPs will have an ASN for their route server, and possibly a >> separate asn for their mgmt infrastructure. >> >> Not sure how useful the mgmt ASN is, although most IXPs will >> paradoxically >> include this on their list of members. >> >> Nick >> >> > Thanks for your help! > > I studied all the AS-Path in the routing table (from routeviews and > RIPE), and found that some ASN of IXPs were included in some AS-Path.
You are likely seeing IP addresses from the peering LAN, which typically have addresses that are under the ASN from an IX. Quite a few IXes state that the peering prefixes should not be announced world-wide. > I think that under normal circumstances they should not appear in the > AS-Path, hence i want to filter out them. "Filtering them out" will have fun results when a valid ICMP is being returned. Something about "Packet Too Big"... What is the reason for thinking you need to filter these? Greets, Jeroen
