Re: DNS Cache Query question

Well, you could become the key registrar that assembles the .com zone
from the collection of registrars, and add a wildcard into the .com
zone. (aka sitefinder) 

There were anti-sitefinder patches to various nameservers, which
detected the verisign wildcard response and did something different.  
Those patches should work for you with a little modification, the tld
response to look for is nxdomain for your case. I don't recall if there
was such a patch for dnscache, though. Its not too hard to do.

But that said, I'd recommend against such shenanigans in the cache
servers, though.  It alters the user experience in a way not easilly
explained as not tampering with their communications; And I think it
kind of breaks the trust of the user in the caching server.

And of course users can use their own open recursor to circumvent your
alterations.

		--Dean



On Tue, 14 Oct 2008, Neil.B wrote:

> Hi DJB Users,
> 
> I would like to know if there is a way to redirect invalid dns queries
> to a selected recursive cache server.
> 
> For example say a user looks up www.1234nodomain.com which does not
> exist. I would like dnscache after checking root servers and return a
> negative response to ask a selected list of dns servers. I want to
> basically send invalid responses for domain names that do not resolve,
> redirecting the query to another specific set of dns servers from the
> dnscache. I plan to trap the request and display a generic webpage.
> Something like a catch all but only for querys that do not resolve. Is
> this possible.?
> 
> Thanks
> Neil.B
> 

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