name resolution issue

[Barry Margolin]

In article <9329ja$1ip at pub3.rc.vix.com>,
Hildreth, John W. <John.Hildreth at allegiancetelecom.com> wrote:
>
>have you registered your anmeserver with network solutions?
>It must be registered with them or another domain name provider for the rest
>of the net to know about it.
>(in fact last time I tried to register a domain with a nameserver that wasnt
>a registered internet name server, the domain name was
>delayed until I fixed it by registering my nameserver)

He did (you could have told this yourself with a simple WHOIS query),
although in this case it shouldn't matter.  Since the nameserver isn't in
the domain being delegated, glue isn't needed.

>On Thursday, January 04, 2001 10:01 AM, zerodivide1101 at my-deja.com
>[SMTP:zerodivide1101 at my-deja.com] wrote:
>> I've looked everywhere I can think of for an
>> answer to this question, but no
>> luck.
>> 
>> I'm trying to host DNS for a friend's domain on
>> my Linux box/cable modem.
>> 
>> There is an A record that points the name
>> "ns.zerodivide.cx" to my IP
>> address, and this is the name that my friend used
>> when he delegated his
>> domain.
>> 
>> Some name servers have no problem whatsoever
>> doing the lookup.  Others, for
>> example shore.net's and earthlink.net's,
>> generally can't.  The odd thing
>> about it is what happens in the copied and pasted
>> nslookup results below.

All the delegation and server configurations for theycomeoutatnight.com and
zerodivide.cx seem to be OK.  I think what may be going on is that
answering this query requires talking to lots of different nameservers, and
the query is timing out.

Let's assume that the only thing in the nameserver's cache is the root NS
records and the delegation records for the GTLDs.  It has to go through the
following queries:

Ask a COM server for www.theycomeoutatnight.com.  It returns a referral to
ns.zerodivide.cx.  Since the nameserver isn't in the same domain, and the
root server doesn't have ns.zerodivide.cx in its cache, no glue record is
included in the response.

Ask a root server for ns.zerodivide.cx.  It returns a referral to the
servers for the CX TLD, and includes glue records for all of them.  I
deliberately assumed above that only the GTLD delegations are in the
nameserver's cache, since there's a pretty good chance than an obscure
country domain (Christmas Island?) won't be cached.  I'm not exactly sure
why these glue records are all being included -- maybe there's a special
hack for TLD glue records.

Ask one of the CX servers for ns.zerodivide.cx.  It returns a referral to
zerodivide.ne.mediaone.net.  This probably won't include the glue record
(some of the CX servers have recursion enabled, and it appears that people
investigating your problem may have caused the A record to be cached, but
ne.mediaone.net TTLs are only 30 minutes so they'll time out soon).

Ask one of the NET servers for zerodivide.ne.mediaone.net.  It will returne
a referral to the mediaone.net servers.

Ask one of the mediaone.net servers for zerodivide.ne.mediaone.net.  2 out
of the 3 mediaone.net servers also happen to be servers for the
ne.mediaone.net subdomain, so you have a 67% probability of getting the
answer, and a 33% probability of getting a referral to the ne.mediaone.net
servers.

In that 33% case, you ask one of the ne.mediaone.net servers for
zerodivide.ne.mediaone.net.  It gives you the answer.

Now you can finally ask zerodivide.ne.mediaone.net for
www.theycomeoutatnight.com.

The next time you try it, most of these answers are in your server's cache,
so it can skip many of the steps and get the answer quickly.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.