Root Hints or Forwarding - Design Question

Nate Campi nate at campin.net
Fri Mar 29 22:20:32 UTC 2002


On Fri, Mar 29, 2002 at 10:52:27AM -0800, Jeff LoSpinoso wrote:
> 
> We have are deploying DNS servers to all of our worldwide head
> offices. The intention is for each DNS server to provide stand-alone
> internal resolution, that is it will run a copy of all internally used
> zones.

Just make sure your refresh time on your zones is at least as low as the
lowest TTL on RR's in the zones you slave. That way if NOTIFY fails, and
your slaves have to use the refresh interval, you don't get records on
your slaves that would be held onto longer than a random caching DNS
server would cache them.

> For external internet resolution, some seem to think that we should
> configure each DNS server to forward to its local ISP's DNS servers,
> others feel that it's best to not use forwarding and allow the
> Root-Hints to work its magic.

Most people would say that you would benefit from an ISPs cache if:

 a) they have reliable DNS servers
 b) they have a large cache on their DNS servers

So if it's a large ISP, they probably meet both those criteria. It's
really up to you, even if they qualify be these standards. I would lean
toward using them in many cases, since response times *should* be really
good to nameservers inside your ISP's network.
-- 
Nate

"Windows 95 /n./ 32 bit extensions and a graphical shell for a 16 bit
patch to an 8 bit operating system originally coded for a 4 bit
microprocessor, written by a 2 bit company that can't stand 1 bit of
competition." 



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