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Re: TLD anycast clouds?

  • From: Elmar K. Bins
  • Date: Wed Oct 05 04:05:08 2005

[email protected] (william(at) wrote:

> >authoritative DNS servers (and their IP addresses) and try that list
> >on the routing registries...
> Assuming that you do that, what would you be your criteria to find based
> on RR if the ip is anycasted or not?

Maybe I overestimate the openness of the people and believe everybody
would drop their documentation there...

~>whois -h
descr:        DENIC eG anycast prefix
origin:       AS31529

The AS object gives a lot more clue then...

aut-num:      AS31529
as-name:      DENIC-ANYCAST-AS
descr:        DENIC eG
descr:        DNS anycast AS object
remarks:      | DENIC eG operates the .de ccTLD registry. DENICs IPv4  |
remarks:      | DNS servers are partial unicast and partial anycast.   |
remarks:      | This object covers the IPv4 anycast setups.            |

Maybe using route servers helps more (coffee!) :-)

> I mean lets suppose that I run dns server at AS0 and peer at location A 
> and also at location B with same ISP with AS1. I might have one dns server 
> at location A and another different one at location B, which means its 
> anycasting. But from peering perspective it would just appear as the
> same path AS0->AS1 no matter what location it is.

That's some kind of anycasting, but from a networking point of view
it's redundant links to the same "thing" ;-)

If you are lucky, you can see different next-hops in the BGP.

> Opposite to that route to the same server might be seen from different 
> peer AS# based on location because of routing policies.

Using views from route-servers that are distant from each other might
improve the picture. The RIPE RIS project may be able to help.



"Begehe nur nicht den Fehler, Meinung durch Sachverstand zu substituieren."
                          (PLemken, <[email protected]>)

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