NS record for the @ entry

[Mark_Andrews at isc.org]

> 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.

	It gets the entire zone contents from the primary.

> 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.

	So you can ask the nameservers for the zone for the list
	of official nameservers for the zone.

> 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.

	SOA stands for Start Of Authority.  All RRs at or below the
	SOA belong to the zone, until a new SOA is reached.  This
	includes NS records.  The parent zone only contains copies
	of the NS records.  If the parent server also serves the
	child zone it will return the NS rrset from the child zone
	and not the parent zone if they differ.

	Mark

> 
> 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 pointin
> g
> > >
> > > 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
> 
> 
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org