ODBC Help - Desperate! Help me please!

I have a SQL Server 2000 setup in our DMZ with ports open from the LAN into
the DMZ. When I try to setup an ODBC connection for MS Aceess so I can get
data links setup from the LAN to the SQL Server it fails. In setting up the
ODBC Connection I get to where it lists the available SQL servers and it
finds our servers inside the LAN but not the SQL Server in the DMZ. I try
to put in the IP Address in place of the system name and I get nothing.
Does this sound like a open port concern? If so, what ports other than 1433
need to be open? What is the best way to troubleshoot this issue?

I am desperate for help on this issue and simply not sure where to turn.

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NC Beach Bum