Finding what NS is used for a subdomain?

Question

Two questions from a dns newb:

1. Is it possible for a subdomain to use a different set of nameservers than its parent domain?
   Eg: abc.ca uses ns.whatever.com and ns2.whatever.com, while sub.abc.ca uses ns.anything.com and ns2.anything.com

2. If this is possible, what is the command to look this up? Would something as simple as this work?

dig ns sub.abc.ca

Answer 1

To be on the safe side you should directly ask the authoritative servers at the parent domain about any NS records for the sub-domain.

% dig +norec @parent sub.example.com. ns

This ensures you'll get the current answer straight from the horses mouth, rather than whatever happens to be in your local recursive resolver's cache.

Answer 2

Yes, you're spot on. Other options include: host -t NS sub.abc.ca