small question re caching only name server syntax

Pete Ehlke pde at ehlke.net
Tue Jul 23 18:33:44 UTC 2002


On Tue, Jul 23, 2002 at 05:54:01PM +0000, Don Low wrote:
> 
> Since I wrote, I've come across the following in O'Reilly's DNS and BIND
> book: "As with primary master and slavename servers, a caching-only name
> server needs a root hints file and a db.127.0.0 file" If this is the case,
> then a forward query to a remote name server would be iterative. Not sure
> why they call it a forward *only* name server then.

I think you're confusing two uses of the word 'forward'. Some people
refer to queries that resolve a name to an address as a 'forward' query.
A 'forward only server' never answers queries itself, it simply forwards
them to another server and passes the answers back to the client.
Servers that answer 'forward queries' themselves generally need root hints.
'Forward only servers' do not.

I dislike the term 'forward query' precisely because it often introduces
this ambiguity.

> One other thing, where are the dns records cached -- in what file.
> 
The server's cache is a data structure in memory (pedantically, it's
actually more than one, but YKWIM) and is not stored in any file. You
can cause the cache to be written do disc using 'ndc dumpdb' for bind8
or 'rndc dumpdb' for bind 9.

-Pete


More information about the bind-users mailing list