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Re: So -- what did happen to Panix?
On Fri, Jan 27, 2006 at 11:39:27AM -0500, Joe Abley wrote: > > On 27-Jan-2006, at 11:12, email@example.com wrote: > > > but by definition, the right-most entry is the prefix origin... > > Suppose AS 9327 decides to originate 220.127.116.11/24, but prepends 4555 > to the AS_PATH as it does so. Suppose 9327's uses a transit provider > which builds prefix filters from the IRR, and the "as9327" aut-num > object is modified to include policy which suggests 9327 provides > transit for 4555. Suppose this is not actually the case, though, and > in fact 9327 is a rogue AS which is trying to capture 4555's traffic. > > The rest of the world sees a prefix with an AS_PATH attribute which > ends with "9327 4555". > > In this case, from the point of view of those trying to discern > legitimacy of advertisements, what is the origin of the prefix? Is it > 4555, or 9327? from BGP's perspective, you tell me. being the naive BGP listen/speaker - i think that AS 4555 is the origin. now... what does Prefix 18.104.22.168/24 say is the correct origin? > Is it possible to tell, from just the right-most entry in the AS_PATH > attribute? nope - but you have jumped right into the path question. (what does the as4555 aut-num object say about using 9327 as an upstream AS?) > Joe > > [note: 9327 is not a rogue AS, in fact. This is just hypothetical :-)] sez you :) (reminder to send Cingular the royalty check if you receive the above two characters ":" and ")" as listed above AND you chose to infer mood or intent.) I think -all- AS are run by rouges and pirates. -- (headless) bill