slow DNS resolution

  • Thread starter Thread starter Rusch
  • Start date Start date
R

Rusch

Every few days DNS resolution slows down dramatically or
times out (Windows 2000 Server, SP4). The only thing
that seems to get it back to normal is stopping and
restarting the service. I've checked all boxes under
Server Options on the Advanced tab in DNS except Disable
Recursion. Running forward and reverse lookup tests work
fine everytime. Auto scavenging is set to 4 days. What
is causing the slowdown?
 
Names that are forwarded are slow or names in your authoritive zones or
both?
From the dns server, check each forwarder you have setup in the server using
netdig or nslookup to see if they reply in good time. Remove any that do
not.
 
Forwarded names become slow only. Authoritative zone is
fine. Replies come in good time for Internet/external
requests, but performance seems to degrade over time.
 
I have to assume this may be related to the forwarders themselfs. Server
walks the forwarder list from top to bottom. If the first two (for example)
stop replying, it can result in longer waits. I would NetMon the DNS server
to see the requests come into the server and see what server(s) it forwards
to and how they reply, etc. This will give you clues as to what is going
on. If it is an internal issue, you should be able to deduce that from
NetMon also. hth
 
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