Having multiple name servers - is it really necessary

[Matus UHLAR - fantomas]

On 02.02.10 14:25, Rob Tanner wrote:
> We have two registered name servers to answer internet queries.  One is on
> site and the other is a service of our ISP.  The problem is that every once
> in a while the secondary server doesn¹t successfully complete zone transfers

Ha! a problem!
- check why it's that often unable to complete transfers.
- what kind of transfers are they? Your domain(s)? What about resolving
  internet domains?

> and the data expires.

Another problem!
zone should expire some time after unability to fetch new one. If that
happend "every once in a while", then there's something broken with the zone
- ordinary zones should have expire times 1-4 weeks.

> I¹m not sure what technically how the server answers
> when queried for addresses it no longer thinks are valid, but even after
> it¹s fixed it takes a while for the bad data to go away.

Away from where? if server has a zone configured, it should only provide the
date in zone, not any cached data.

>  What I¹m wondering
> is, what are the consequences of simply not using the secondary server.

you won't be able to resolve if your primary fails.

> Right now we are looking at hardened appliances configured into a high
> availability cluster and I figure the pipe to the outside has a high
> likelihood of going down then does the cluster.  So, if name servers out in
> the internet can¹t even reach our server because our connection is down, is
> that something that also propagates and get¹s cached (i.e. Is no data
> treated the same as bad data by upstream bind servers?

No. However I'd focus on problems of your secondary server.

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Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
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