Time out for a terminology check--"resolver" vs "server".

Larry Sheldon LarrySheldon at cox.net
Sun Feb 14 19:55:51 CST 2010


On 2/14/2010 7:48 PM, Scott Howard wrote:
> On Sun, Feb 14, 2010 at 5:19 PM, Larry Sheldon <LarrySheldon at cox.net> wrote:
>>> It is possibly to run both Authoritative and Recursive server on the
>>> same IP, but it's generally not recommended for many reasons (the most
>>> simple being that of stale data if your server is no longer the
>>> correct nameserver for a domain, but it's still configured to be
>>> authoritative for that domain).
>>
>> Seems like TTL management would take care of that but I think the issues
>> of recursion are now different from the safe world I thought I lived in
>> 20 years ago.
> 
> TTL's play no part in how any Authoritative server answers a request.

I understand that--but it the TTL is being managed correctly the server
answering authoritatively ought to stop doing so when the TTL runs out,
since it will not have had its authority renewed.

> Consider what happens if your DNS server was authoritative for
> example.com, and the .com nameservers pointed to you for that domain.
> Your customer who owns the domain then changes the delegation to
> another provider (and/or the domain expires, etc) but doesn't tell
> you.
> 
> At this point, your server is still answering all requests for
> example.com - because that's what authoritative servers do.  It won't
> check to make sure that the domain is still delegated to it, and doing
> so would make no sense in a generic sense (eg, it might be an internal
> only domain, or testing a new domain that hasn't yet been delegated to
> you, etc).

The glue and all of that stuff won't expire at TTL=0?

I'll have to study that a bit.

Seems like the zone file shold have been replaced to reflect the
authority change.
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