Subject: gTLD server losses

From: Tim Seaver <[email-masked]>
Date: Tue, 17 Apr 2001 12:08:08 -0400 (EDT)

I apologize to VeriSign for mis-stating my gTLD performance results. What
I was actually seeing in my DNS tests was a regular 4% loss from the two
gTLD servers closest to me, c and g. However, this loss was due to the
servers being unresponsive for two 30 minute periods per day during zone
reloads rather than being overloaded. With the move of g on April 4, it
no longer shows that behavior, and Matt tells me that c will be moving
to a new configuration shortly to avoid the reload outages. That's
good news, since it should remove some 20% of the server retries I see.

Thanks,

	Tim

 > Tim, could you please elaborate on your #1 below?  I'm not sure if you're
 > attributing the short TTLs to the {com,net,org} zone contents.  But I just
 > wanted to point out that although all delegations in the {com,net,org} zones
 > have a 48-hour TTL, that should have little effect on how long a zone's NS
 > RRset is actually cached.  In any BIND name server since 4.9, as well as the
 > Microsoft DNS server (at least the W2K version--don't have an NT 4 system
 > handy to test), the NS RRset in the delegated zone overrides the RRset
 > obtained from the parent.  So NS RRsets for subzones of {com,net,org} with
 > "short" TTLs are an issue with individual zone administrators.

 > What do you mean by "overload of gTLD servers"?  We've sized the
 > {com,net,org} name servers very carefully and monitor the query volume in
 > real time.  We have lots of headroom and have yet to come close to our
 > maxmimum.  I'd be very interested in any data you've got--I wouldn't like to
 > think we've missed something.

 > Thanks,

 > Matt
 > --
 > Matt Larson <[email-masked]>
 > VeriSign Global Registry Services / www.verisign-grs.com

 > > I'm in the middle of a DNS performance study. Right now, I can
 > > say with confidence that most DNS performance problems from my
 > > perspective in the network/DNS topology come from:
 > > 
 > > 1) Short TTLs on second-level NS records combined with overload of
 > > gTLD servers, leading to caching server retries for delegation data.