Bill Parker writes:
> At 11:07 AM 8/12/99 -0400, you wrote:
> >*Always* run a nameserver on your qmail machine, even if it's caching-only.
>
> Ummmm, i'm a little confused here, I don't admin my own DNS (UUNET does
> that for me), is there a difference between DNS and a caching nameserver?
I agree, it's confusing. Let me try to explain. The DNS (domain name
system) is a big distributed database (unquestionably THE most widely
distributed database), shaped like a tree. The tree starts at the
root, which holds top-level domains: the gTLD's (.net, .com, .edu,
etc.) and ccTLD's (.us, .uk, .pl, .to, etc.) Then you get into
second-level domain names, and third, etc.
You *could* quite easily construct a client which always recursed the
whole tree, starting at the root. That would be very slow. Instead,
what happens is that the client *always* asks a local server
(sometimes on the same machine). The server will do the recursion if
it doesn't have a timely cached answer from a previous query.
There is no requirement that your clients' nameserver be the same
nameserver that is authoritative for your domain. Important
characteristics for your authoritative nameserver (reliable access
from the rest of net) are different than those for your client's
nameserver (tons of memory for storing all the hostnames you send
email to).
> if so, will a caching nameserver speed up web queries by the machines
> who get their net access via the linux box (NAT)?
Yes. You should always have a caching nameserver which is local to
the clients which access it. Whether that's the same machine running
qmail, or whether it's a dedicated machine depends on the exact mix of
email you send and receive.
--
-russ nelson <[EMAIL PROTECTED]> http://russnelson.com
Crynwr sells support for free software | PGPok | Government schools are so
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