caching only + wildcard

Kevin Darcy kcd at
Thu Jun 26 02:29:25 UTC 2008

idanj wrote:
> Hello all,
> We have 2 BIND name servers configured as "caching-only".
> Is it possible to set a wildcard A record ("catch all") on a these
> name server?
> The problem is that when the server gets a query for a domain that
> doesn't exist in its cache, the server will return the wildcard reply
> instead of checking the root servers first.
I'm confused about what you're trying to accomplish here. Are you saying 
"return a wildcard record any time the answer is not in cache"? Even if 
that were possible, how would you expect to *ever* get anything into 
your cache in that case? Bear in mind that a caching-only nameserver 
typically starts up with *nothing* in its cache, just some "hints" 
information about where to find root nameservers. If you give back a 
wildcard record for everything not in cache, then there's no reason to 
*ever* go out and resolve *anything* or cache *anything*. You just give 
the wildcard record for every query. You might as well be not even 
connected to the Internet.

I must be missing something here. Could you please clarify?

Are you perhaps using the term "cache" to also cover 
*authoritative*data*, i.e. where your (so-called) "caching-only" 
nameserver is also master or slave for certain select zones, and you 
want everything *else*, not in those zones, to get a wildcard response? 
In that case, maybe your requirement might make sense...

Or, could it be that you're trying to set up a DNS infrastructure on an 
internal network, that has no connectivity to the Internet? If so, then 
you're approaching it the wrong way. You don't want "wildcards" to 
prevent your nameservers from going out and trying to talk to the 
Internet root nameservers; what you want is to set up your *own* private 
root zone, and point all of your nameservers at that root zone instead 
of the Internet version.

                           - Kevin

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