Can Not Access Clustering SQL Server After Relocation

Hi all:

I have a clustering SQL Server on Node1 and Node2, the Node1 has named
Instance1 and Node2 has named Instance2, no default instance. We
tested it that everthing is OK, then we decide to move to DR location.

The relocation kept the same virtual and phusical server name, and we
did not change SQL Server server network utility. But server IP
addresses were changed(vitual and physical). We can start the
clustering SQL Server as before, and everything looks like well.

However the users can not access it remotely, and they did not change
the client network utility. But if I login the server,I can access it
from Query Analyzer even though ther is not client network utility
setup on the server. I can ping the vitual server name, how can I make
sure the ports are working well? (We did not use the default port for
named instance).

I remember I did input the virtual server IP address when I installed
the clustering SQL Server. Of course, it was change after relocation.
Is it the reason for failed remote login? If it is, how to fix it?

Does anyboday know there is document for clustering SQL Server
relocation?

Thanks
Willie