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Re: How to tell if something is anycasted?
well Peter, ONE root server operator has that practice. Others have different practices regarding anycast. --bill On Tue, May 16, 2006 at 11:59:54PM -0700, Peter Boothe wrote: > > On Tue, 16 May 2006, David Hubbard wrote: > > > So I'm looking at a company who offers anycasted DNS; > > how do I tell if it's really anycasted? Just hop on > > different route servers to see if I can find different > > AS paths and then do traceroutes to see if they suggest > > the packets are not ending in the same location? > > >From my routers' perspective I don't see a difference, > > but then I don't think I should, correct? > > If they conform to the convention that the DNS root servers practice, then > a dig query from several locations should suffice. Choosing an anycasted > DNS root at random, you can do > dig @f.root-servers.net hostname.bind chaos txt > And the response should include a line like > hostname.bind. 0 CH TXT "pao1b.f.root-servers.org" > > >From other locations, it might be "sfo2c.f.root-servers.net" or somesuch. > If they don't do that, then you are stuck with more ad-hoc methods like > traceroutes from many different locations, or checking out AS-PATHS in > Routeviews and using your intuition. > > -Peter > > -- > Peter Boothe > PhD Student "Young man, you think you're very > Computer Science smart, but it's turtles all the way > University of Oregon down!" > http://www.cs.uoregon.edu/~peter