Question about forwarders...

[Joseph S D Yao]

On Tue, Sep 19, 2000 at 11:58:04PM +0000, Kees Hendrikse wrote:
> Brian Thomas <wolfie at boldfish.com> wrote:
> > For the record, the situation is I have is a large farm of MTA's 
> > delivering mail to many recipients. I want to run a caching-only
> > server on each of those MTA's for speedy lookups, and have two (Or more)
> > dedicated servers to act as forwarders for outbound lookups. That should
> > limit the Internet traffic (Since the caching servers will never talk
> > over the 'net link), and insure the dedicated forwarders have large
> > caches for multiple lookups on the same domain.
> 
> You could change the order of forwarders on different MTA machines. Half
> of them would use A first, B second, the other half B first, A second.
> But why use caching-only setups at all? All your MTA's could talk directly
> to the two (or more) DNS servers with outside access. I don't see the gain
> of using local (to the machines) caching-only servers. The DNS traffic is
> probably neglectable to the traffic generated by the mail messages.

If you like the idea of having separate caching name servers, you still
should not run them on the sendmail machines.  I am finding that
running sendmail and DNS on the same machines is quite possible, but it
takes a LOT of resources.

Run sendmail [or postfix] on your MTA machines.  Run a large name
server on a separate but fast [network-wise] machine.  Have only one,
so as not to dilute the cache.  If you want to have this machine also
query external name servers, I don't see why you wouldn't.  Have your
internal name server, though, be on a separate machine, so that zone
maintenance does not affect the caching name server.

-- 
Joe Yao				jsdy at cospo.osis.gov - Joseph S. D. Yao
COSPO/OSIS Computer Support					EMT-B
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