search lists or hermit crabs

Barry Margolin barmar at bbnplanet.com
Fri Nov 5 17:31:54 UTC 1999


In article <1FDFA88B3AABD211B8D800105AAB89B40110A48F at wak-mail1.btrd.bostontechnology.com>,
Downs, John <JDowns at comversens.com> wrote:
>
>      When I do an nslookup on "bts63t01.i.bts63.comversens.com" (with no
>dot) the query will first
>append "i.bts63.comversens.com", then it will append "bts63.comversens.com"
>and finally it
>looks for the correct name.   So the first query will look like:

What OS?  This used to be a common misbehavior, but most current resolvers
have fixed it.

>    bts63t01.i.bts63.comversens.com.i.bts63.comversens.com
>
>the rcode for this query is "NXDOMAIN"  
>
>What does NXDOMAIN mean? None-existent domain?

Yes.  It's referred to as "Name error" in the DNS RFC's.

>The second query starts without any delay and looks for :
>
>
>bts63t01.i.bts63.comversens.com.bts63.comversens.com
>
>On this query it times out three times for a total of 42 seconds.
>the opcode of query returns an rcode of SERVFAIL.
>
>Why do I get two different rcodes and why is it timing out?

The server in your resolv.conf is probably authoritative for the
i.bts63.comversens.com subdomain, but when you ask for something outside
that subdomain it goes to the main comversens.com servers.  There appears
to be a misconfiguration of the bts63.comversens.com subdomain on those
servers.

>They next query looks for :
>
>bts63t01.i.bts63.comversens.com
>
>and returns the address correctly. But the whole process takes almost 60
>seconds and impacts
>telnets and rlogins..
>
>Any ideas?

Upgrade your resolver.  The correct behavior is to try the name as given
first if it has any dots in it.  If not, or if that first query fails, it
should then try the domains listed in the resolv.conf "domain" or "search"
settings, and it should not automatically go up the hierarchy.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, 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.


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