NS records different then domains ACTUAL Name servers?

[Barry Margolin]

In article <c1ltga$1j8o$1 at sf1.isc.org>,
 michaeljames2k at hotmail.com (MichaelJ) wrote:

> Ok, hope i dont confuse anyone.
> 
> Say you have 2 name servers, ns1.newhost.com and ns2.newhost.com.
> 
> You have a domain name, domainname.com, whose official name servers in
> it's WHOIS record is ns1.oldhost.com and ns2.oldhost.com.
> 
> Say we create the EXACT same record on newhost's name servers as
> exists on oldhost's name servers, including the NS records.
> then, we go to the Registrar and modify that name servers to
> newhosts's.
> 
> So that the whois record might look like this:
> 
> ns1.newhost.com
> ns2.newhost.com
> 
> And on ns1.newhost.com and ns2.newhost.com, the DNS record looks like
> this:
> 
> domainname.com.          IN NS  ns1.oldhost.com.
> domainname.com.          IN NS  ns2.oldhost.com.
> 
> 
> Now, will this work? Will the DNS request be forwarded over to the
> oldhost.com's name servers, and the record grabbed from there?? A
> client wants us to do this, but we've never done it before.

No.  If the delegation points to ns1.newhost.com, it will be expected to 
respond authoritatively for names in the domain.  It can delegate 
subdomains to other servers, but it can't re-delegate the domain itself.  
In other words, delegation only works as you go down the DNS hierarchy, 
it doesn't work sideways.

However, you said above that you create the same records on the newhost 
servers as on the oldhost servers.  If that means you copy all the 
records within the zone as well, then things should be OK, since the 
newhost servers will be able to answer queries.  What will often happen, 
though, is this: when the newhost servers answer, they'll include the NS 
records in the Authority Section, and the caching server will replace 
the NS records in its cache with these.  From then on (until the NS 
records' TTLs expire) the caching server will query the oldhost servers.

-- 
Barry Margolin, barmar at alum.mit.edu
Arlington, MA