enable DNS

[Jeff Vian]

Kenneth Porter wrote:

> --On Saturday, June 12, 2004 6:50 AM -0500 Jeff Vian 
> <jvian10 at charter.net> wrote:
>
>> Your caching nameserver still needs to query some other server for
>> lookups and setting that as the only nameserver in resolv.conf will 
>> break
>> dns for you.
>
>
> How will it "break DNS"? Works fine on my mail servers, which do a 
> *lot* of lookups, not just for regular domains but also for dnsbl's.


The caching nameserver has to query something to get the IP addresses 
for name resolution.  If there is not an entry in resolv.conf (for the 
nameserver host) that points to the ISPs nameservers then named has to 
rely on the default config (unless modified by the user) . The default 
config for named points to the root nameservers, which means several 
queries for each host lookup, and lots of everhead.  This slows down the 
access, and should not be used because of the distributed design of DNS.

Proper configuration here is important, and as Rudolfo has said, caching 
nameservice for one or a few machines is not optimal.  Doing caching 
nameservice (properly configured with nameserver addresses) for a 
network for lots of machines becomes efficient and better than having 
each mach go to the remote nameserver.

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