NS record for the @ entry

[Barry Margolin]

In article <37BD2B5E.57A53E81 at hk.china.com>,
Edmund  <c990077 at hk.china.com> wrote:
>Also, I remembered that a post has mentioned before that if there's
>no NS record related to the @ entry, the BIND DNS server won't
>start up.  However, what I still can't figure out is that if some client

It will start up, but it will complain and make itself non-authoritative
for the zone.  This is similar to what it does if it notices a syntax error
in the zone file.

>query my DNS server for a record which is not NS type in my zone,
>then I don't need to have a NS record associated with the @ entry
>to answer the query.  So, why is it necessary to have at least one
>NS record asssociated with the @ entry.

It's a sanity check.  If there's no NS record, a common reason could be
that you made a typo.  For instance, if you do:

mydomain.com  IN NS  ns1.mydomain.com.
mydomain.com  IN NS  ns2.mydomain.com.

The missing "." at the end of "mydomain.com" will cause these to be treated
as:

mydomain.com.mydomain.com.  IN NS  ns1.mydomain.com.
mydomain.com.mydomain.com.  IN NS  ns2.mydomain.com.

rather than the top-level NS records that were intended.  Without this
check, you would never notice this serious error.

-- 
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.