[QUESTION] Delegating zone

[Mathias Körber]

> > @       IN      SOA     NSS1.subdomain.com. admin. (
> >                                         2001022602
> >                                         14400 
> >                                         1800 
> >                                         2592000 
> >                                         1800    )
> >                                 IN      NS
> > NSS1.subdomain.domain.com.
> >                                 IN      NS
> > NSS2.subdomain.domain.com.
> >                                 IN      NS      NSS3.otherdomain.com.
> > 
> > Is NSS3.otherdomain.com. authoritative of subdomain.domain.com.???
> 
> This is a form of lame delegation though its not so harmfull. Yes,
> nss3.otherdomain.com. will be authoritative if its configured as such. Its
> however unlikely that nss3.otherdomain.com. ever will be queried, since no
> resolver will learn from ns1.domain.com that nss3.otherdomain.com. is
> authoritative. In other words, why not have all listed in the parent zone
> (at ns1.domain.com) to divide the load. 

Actually, initial queries for this zone (when still unknown to a resolving nameserver)
will only go to NSS1 and NSS2. After that resolving NS has learnt the full NS RRset (including
NSS3), it will remember this (more authoritatively known) set and also use NSS3 for
further queries for that zone, until this RRset expires.

 
> Have the _exact_ same set of authoritative nameservers in the parent zone
> (as glue) as is listed (and thus authoritative) in the child zone.

That is recommended