NS record for the @ entry

[Edmund]

Might be my concept is not clear.  The SOA, to my understanding,
is used in the zone transfer between the primary DNS server and its
secondary DNS servers, and the secondary DNS doesn't have a
pre-configured SOA entry because it will get it from primary DNS.
But I don't understand why the @ entry has to have at least one
NS record associated with it since its' parent zone name server
already has a NS record pointing to it.  You mentioned that it's
required because it's the definition of zone.  But I still don't understand
why such definition is required and what it is used for.

Michael Voight wrote:

> What do you mean the NS record for the SOA.
> The SOA and NS record are 2 different things.
>
> There is no requirement for you to have an NS record for the primary
> server. You may not want to advertise that machine as a nameserver.
>
> Michael
>
> Edmund wrote:
> >
> > Thanks.  Can it be possible that the NS record for the SOA is not pointing
> >
> > to the local machine ??
> >
> > marka at isc.org wrote:
> >
> > > > Does anyone know why there must be a NS record for the @ entry ?
> > > > As my understanding, the NS record is pointing to the local machine
> > > > and it is the local machine the SOA for this zone, so why is the NS
> > > > record still necessary for the @ entry ???
> > >
> > >         Because that is the definition of a zone.  All zones contain
> > >         a SOA record and a NS RRset at the top of a zone.  NS records
> > >         in parent zones are supposed to be *copies* of the child zones
> > >         NS records.
> > >
> > >         Mark
> > > --
> > > Mark Andrews, Internet Software Consortium
> > > 1 Seymour St., Dundas Valley, NSW 2117, Australia
> > > PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org