Suspecious anycast prefixes

John Kristoff jtk at
Thu May 5 13:10:31 UTC 2011

On Thu, 5 May 2011 11:54:17 +0300
Joe Abley <jabley at> wrote:

> Perhaps I'm misunderstanding the original question, but the assertion
> that anybody is hijacking that particular prefix seems false.

Furthermore, that exchange prefixes may often appear to be anycast is
not unusual.  Those prefixes are often originated by multiple disparate
networks who are connected to the exchange.  In a lightning talk I did
at NANOG 41, I talked about mapping peering relationships at exchanges.
When I noted that these prefixes are often announced by exchange
participants, Louie Lee explained that some of his participants often
announce the space to their transit customers so that monitoring and
troubleshooting tools don't cause confusion (e.g. traceroutes).


More information about the NANOG mailing list