I would appreciate some suggestions or pointers as to where to look
for, to increase a java server's ability to accept a huge number of
simultaneous connections.

Using the backlog feature in java's ServerSocket or NIO hasn't solved
my problem.

Details:
I have java socket server which accepts connections from clients. These
are persistent connections. I also have a thread pool in the server to
read/write to the clients
I did a performance test. I created 100 connections from 8 machines and
continuously read/write data using the connections.
I have problems creating lot of connections. even though the client
retries 50 times before it gives up.
Out of the attempted 800 client connections 300 seem to fail.

I am using the backlog feature in java's ServerSocket. It is set to
400.

My server is Windows 2000. Is there a setting to increase the number of
sockets for an application? Am I hitting some OS socket limit?

I have tried using NIO too. It doesn't seem to work.