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