should nslookup resolve by using single-labels

HI,

Im not sure if nslookup should resolve by using single-labels or not,
but i get mixed results when i run it...

We have 4 child domain sites, some of which can, when from inside
nslookup resolve some of the child domains using the single label; ie
northwest returns same as northwest.rootdomain.internal northeast
returns same as northeast.rootdomain.internal but never returns just
rootdomain, rootdomain.internal works fine.

even from the PDCE (also DNS server) or any other rootdomain server, no
return is given from nslookup without giving the FQDN for the
rootdomain.

all the sites are linked via router to router vpn, and sit in there own
site in sites and services.

The DNS is setup so each domain uses its own AD zone set to replicate
round with secondarys added.

we dont see any sysvol problems, but this maybe stopping our DFSR from
being fault tolerant as it cannot find the rootdomain without the FQDN.

Cheers

Phil