naming dns servers

Barry Margolin barmar at genuity.net
Fri Aug 24 00:24:29 UTC 2001


In article <9m44oq$2ge at pub3.rc.vix.com>, iTypical Male  <mr_t at dr.com> wrote:
>I've been learning about DNS, setting up, etc, etc lately, but I still
>have one question. Many times when you whois a domain (let's say
>domain.com), you'll see it's name servers listed as something like
>ns1.domain.com. I'm confused since clients look up your DNS server to
>get your IP address, how could your DNS server have a subdomain itself?
>I know it can, obviously, since many servers are set up that way.  How
>do you setup your name server to use a subdomain of your domain?

This is a very astute question.  The solution is something called "glue
records".  If the name of the server that's hosting a domain is within the
domain itself, the parent domain has to have a copy of the address record
for the hostname.

So in the COM domain, the following records will exist:

domain.com.     IN NS  ns1.domain.com.
ns1.domain.com. IN A   1.2.3.4

That A record is a glue record.

When a query comes to the COM nameserver for something in the domain.com
domain, it will return *both* of these records in the referral.  This
avoids the chicken-and-egg problem.

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, 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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