Not Windows firewall - unless you make an exception for a programme it just blocks it....

But Limewire claims that with XP and Windows Firewall, support in the Limewire app is intergrated, making temporary exceptions when you have Limewire running, to allow Limewire access through the firewall, which then shut again when you exit the programme....

In my expirience, thats not strictly true tho - not on my PC (I have Windows Firewall turned off as I have Zone alarm instead) and my sisters PC won't allow Limewire through even after I manually added it to permanent exception, and forwarded it a specific port through the router....

Turn it off however, works fine!