[geeks] simple DNS / nslookup question

[kevin marshall]

I'm trying to help my mother with an email server/MX record issue and
have run across a question i've had for a while, i just never really 
needed an answer until now.

If you run nslookup as such, against a domain, without a host name 
specified:

#nslookup yahoo.com

You will receive a response.  This does not work for all domains 
however.  What type of record is this response (domain queries lacking a 
specific host name) and how do i set up something like this in bind?

Of course i would get an MX record if i set type=mx and queried just a 
domain, but i'm talking about domain only queries with no specific type set.

Thanks,
/KRM

FYI: Her actual problem is getting her email server (nbww.com) to send 
mail to pjgeng.org, but the DNS for pjgeng.org is screwed (no MX record).