Confused about DNS issue

[Chris]

"The Other Mike" <noone at nowhere.net> wrote in message 
news:dak0b8$1sno$1 at sf1.isc.org...
> Trying to diagnose an email issue to a certain domain.   Doing an
> NSLOOKUP for the MX record on this particular domain it comes back
> with a server name (say server.domain.com).  Now, when I ping
> server.domain.com, it does not resolve an IP address.  I did this from
> our west coast office and from my home PC on the east coast (different
> ISP's) and neither resolve an IP.  But...if I go to www.dnsstuff.com
> and use their ping, it does resolve an IP.  Also if I do a ping -a
> using the IP from dnsstuff on my home PC or work PC, it will
> successfully do the reverse lookup and return server.domain.com.  Can
> someone enlighten me as to what might be going on??   Why can I get
> the reverse lookup but no host resolution using 2 different
> ISP's...and why does dnsstuff.com get both with no problem??
>
>

It would help of course if you told us the domain in question. Without 
knowing that how could we possibly know what the problem might be? Also, 
which DNS are you using that can't resolve it?

Chris.