[dns-operations] Too Open (Was: OpenDNS makes your Internet work better

brett watson brett at the-watsons.org
Fri Jul 14 04:06:21 UTC 2006

On Jul 13, 2006, at 7:53 PM, Nicholas Suan wrote:

> Who says there's any routing-fu involved?

i believe brad, in a previous post, indicated that "anycast tricks"  
were being used.

> In the root zone, (I use it
> as an example since some of the nodes are anycasted) if one server
> times out, it's no problem for a resolver to go and check another
> instance of the root, which will most likely be located someplace that
> isn't malfunctioning.

by "instance of the root" do you mean "an instance of the same root  
server" or do you mean "another root server"?

> This was not the case with UltraDNS, as both IP
> addresses in the NS records for org. were anycasted.

so this was... a *long* time ago. any modern implementation i've seen  
of anycasted resolvers (f-root, k-root, and ultra come to mind) works  
such that when the resolver no longer responds for some reason, it's  
prefix is removed from the global routing table immediately and any  
subsequent queries that might have reached that node happily shuffle  
along to the next path in the global routing table to the next  
closest node, and all is well.

why are people arguing about a condition that happened years ago that  
no longer exists?


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