[90351] in North American Network Operators' Group
Re: How to tell if something is anycasted?
daemon@ATHENA.MIT.EDU (bmanning@vacation.karoshi.com)
Wed May 17 10:47:45 2006
Date: Wed, 17 May 2006 14:45:41 +0000
From: bmanning@vacation.karoshi.com
To: Peter Boothe <peter@cs.uoregon.edu>
Cc: David Hubbard <dhubbard@dino.hostasaurus.com>, nanog@merit.edu
In-Reply-To: <Pine.SOL.4.58.0605162352160.20584@ix.cs.uoregon.edu>
Errors-To: owner-nanog@merit.edu
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
