From: Elmar K. Bins (no email)
Date: Wed Oct 05 2005 - 04:00:52 EDT
(william(at)elan.net) 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 whois.radb.net 194.246.96.1
route: 194.246.96.0/24
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.
Cheers,
Elmi.
--
"Begehe nur nicht den Fehler, Meinung durch Sachverstand zu substituieren."
(PLemken, <bu6o7e$e6v0p$2 at ID-31 dot news dot uni-berlin dot de>)
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