[932] in resnet
Re: DNS Issues - Random EDU lookup failures
daemon@ATHENA.MIT.EDU (Rick Cox)
Fri Mar 1 17:53:57 2002
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Message-ID: <Pine.LNX.4.44.0203011359430.26325-100000@hal.rescomp.berkeley.edu>
Date: Fri, 1 Mar 2002 14:28:24 -0800
Reply-To: Resnet Forum <RESNET-L@listserv.nd.edu>
From: Rick Cox <rick@RESCOMP.BERKELEY.EDU>
To: RESNET-L@listserv.nd.edu
In-Reply-To: <A17AA9D6C953D640B218FCB1EB21619614E9EB@EXCHANGE.campus.stcloudstate.edu>
Hi,
I think this may be the correct behavior for root servers J-M. The root
servers primary function is to resolve the first component of the name,
telling clients what server has the domain records for .edu or .com or
.uk, for example.
As it happens, for a long time, the root servers had second function of
resolving the "generic" (none-country code) top-level domain records as
well. Thus, they would provide the NS records for '.inktomi.com'
directly, though all they were really required to do was resolve the
'.com' part. In the last few years, however, this service has moved
partially off the root servers; .com in particular is now served entirely
by [A-M].gtld-servers.net. Perform a .com query against a root server, and
you'll just get a referral to these gtld-servers.
Edu is still served by a subset ([A-I].root-servers.net) of the root
servers. These servers will answer queries directly for domains like
washington.edu or stcloudstate.edu, returning the NS records for those
domains. The remainder of root servers (J-M), however, do not keep the
.edu records. Thus, they provide a referral to the TLD servers for .edu
instead (which happen to be [A-I].root-servers.net).
rick
On Fri, 1 Mar 2002, Forseth, Clint G. wrote:
> We have been getting reports from several off site persons who are
> experiencing email delays or inabilities to get to our domain
> stcloudstate.edu. The problems appear to have started sometime around
> 2pm yesterday(that we are aware of).
>
> Myself and another systems administrator have been banging our heads
> against a wall searching for the cause. Since it appears random and
> nothing has changed on our site (DNS settings wise) we started looking
> to the root servers. We noticed that the root servers J-M do not appear
> to resolve the NS servers for our domain or any EDU domain. The others
> appear to be resolving the EDU domain just fine.
>
> In theory, it seems that the root servers J-M are not aware of the EDU
> domain site NS servers. We gathered that theory based on that the
> others A through I are resolving the name servers for our domain and for
> other EDU(s). There appears to be no problem with A through I resolving
> our ns servers and then for our servers to respond to external requests.
> Just with J through M.
>
> Is anyone else experiencing anything like this or have any better
> theories or ideas? I'm not totally up-to-speed on how the round robin
> works for the root servers (which one a site checks and how often).
> The local cable modem users on Charter were unable to reach us last
> night and today and we've seen similar problems on other ISPs and with
> email from multiple sites being delayed. I've connected to some other
> known DNS servers out there doing nslookups and was unable to resolve
> EDU(s) on some them that I was testing on.
>
> Any sound ideas or knowledge into this would be appreciated.
>
> Thanks in advance, Clint Forseth Systems Administrator St. Cloud State
> University - Go Huskies Hockey! (okay, shameless plug, but I get
> excited easy this time of the hockey season).
>
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