NSLOOKUP not finding domains (newbie question)

[Sparhawk]

Hi all.
Apologies if this is the wrong group for this question.
I am using NSLOOKUP to try to find domains that my DNS can't locate
(Microsoft DNS on NT4 SP5) then placing the MX record IP address  in a
HOSTS file for e-mail lookups.  It tends to work fairly well.  But,
recently we have received incoming mail from domains in IE (Ireland) and
CO (Columbia, I think) but cannot reply.  NSLOOKUP can't find the
domains.  I pointed NSLOOKUP at our ISPs DNS, but it couldn't find the
domains either.

Is there some other tool for doing domain lookups?  Also, I thought if
you had a domain like company.com.co, it had to have a root domain of
"co".  However in this case the root domain seemed to be "com".(??)

TIA for any advice!!!


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