nanog mailing list archives

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


From: Larry Sheldon <LarrySheldon () cox net>
Date: Sun, 14 Feb 2010 19:55:51 -0600

On 2/14/2010 7:48 PM, Scott Howard wrote:
On Sun, Feb 14, 2010 at 5:19 PM, Larry Sheldon <LarrySheldon () 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.
-- 
"Government big enough to supply everything you need is big enough to
take everything you have."

Remember:  The Ark was built by amateurs, the Titanic by professionals.

Requiescas in pace o email
Ex turpi causa non oritur actio
Eppure si rinfresca

ICBM Targeting Information:  http://tinyurl.com/4sqczs
http://tinyurl.com/7tp8ml
        


Current thread: