what sort of firewall.. yours or someone elses? A program you have or windows xp firewall... Have you a router with a firewall..
You have to tell your firewall the program name, and the port number and protocol it uses. To get around the protocol you can often enter the program twice with different settings..
example . c:\program files\limewire\limewire.exe (program name)
UDP port 6884 or TCP 6884 (find out port no. from limewire menu.
mart9012, June 2007