why need cache if has forward-only

[Mark_Andrews at iengines.com]

> Hi,
> 
> can someone that a look at this... this is a corp subdomain DNS server.
> 
> In my named.boot file I have
> 
> forwarders    10.20.30.40 ; corp root dns
> option forward-only
> [....]
> cache     .      named.cache
> 
> 
> In my named.cache file I have
> 
> ..    IN    NS    dbna.com.
> dbna.com.   IN   A   10.20.30.40
> 
> 
> My questions are
> 
> 1) in general, if I use forward-only, then do I need a cache file? The cache
> file lists root servers that I would query without a forwarder directive or
> if forwarder fails. Since all non-local-domain lookups are only going to the
> forwarders, why do I care where the root servers are?

	You do for BIND 4 and BIND 8 up to but not including BIND 8.2.1.
	forward only is broken in BIND 8.2.
> 
> 2) in my case, the corp root DNS is my forwarder. So even without a
> "forward-only" option, I don't need the cache file, right?

	The answer is independant of whether the forwarder is the root
	server or not.
> 
> 3) unrelated to the files above.... I know named will cache results for name
> lookups outside of my domain. How do I know how many results have been
> cached, where are they cached, which ones are cached, etc.? Is there a tool
> to examine the cached results?

	They all are.  You can dump the cache if you want.

> 
> Thanks, responds by email would be great.
> 
> Clayton
> 
> 
--
Mark Andrews, Internet Engines Inc. / Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at iengines.com