Urgent :Rejecting client IP address to specific port

From: Gopal (oracleinform@yahoo.com)
Date: 11/29/02 

From: oracleinform@yahoo.com (Gopal)
Date: 29 Nov 2002 01:15:01 -0800

Hi All,

       Just a simple question ,can I reject the client IP address to
specific port through firewall or proxy server rather than the IP
address itself.

Thanks,
regards