Delegation

[Chris Buxton]

BIND 9.3 and later will use RTT with the forwarders list. (This is  
better than round-robin.)

A server that forwards a query to another server will cache the  
result. To suppress this, set your TTL's on the authoritative server  
to a very low number, such as 5 seconds, or even 0. Note that this is  
generally not good practice, but while you are testing, it may be  
warranted.

If you were to somehow disable caching at the server by setting max- 
cache-size, or something like that, the client machines would still  
tend to cache records. Setting a low TTL solves that problem as well,  
although some clients (e.g. Mac OS X's resolver service) will still  
cache for some amount of time (typically applying a minimum of no more  
than 1 minute).

Chris Buxton
Professional Services
Men & Mice
Address: Noatun 17, IS-105, Reykjavik, Iceland
Phone:   +354 412 1500
Email:   cbuxton at menandmice.com
www.menandmice.com

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On Feb 15, 2008, at 2:43 AM, John Bond wrote:

> Thanks for the responses everyone i guess its back to the drawing
> board.  I think i will have to use the forwarders option and include
> all three of the boxes in the new infratructure.  If i where to do
> this, will the dns boxes which are forwarding round robin the three
> forwarders if not i can to this load balancing at the firewall.  Also
> will the box doing the fowarding cache the dns results or will it
> foward all requests.  If it performs cachijg can this be disabled.
> Thanks agaiin
>
>