Network Performance Problem Runnin HTTP Dominos 6.5 on Windows 2003

Hello.

We have recently migrated a Lotus Dominos 6.5 database from Windows 2000 to
Windows 2003.

If we use a browser on that server to access the database locally, the
response time is great. However, if we try to access the database over the
network, the response time is awful.

The server is ok as far as CPU and RAM use (less than 5%). The same
database runs very fast when accessed over the network on a similarly
configured Windows 2000 machine. I think it must have to do with some
settings in Windows 2003 network buffering and/or caching and Dominos
defaults ... Any ideas?

Thanks