Your router has a NAT firewall. This might be what LW is recognising. You might have to port forward. It's no drama, just takes a little time

First though, I'd give your ISP a call & just see that they haven't started blocking p2p. It seems strange that this happened out of the blue! Do this first, so that you don't go through the whole p/f thing for nothing!

Here's the p/f info anyway, just in case you need it

Step 1. Set up a static IP address
http://www.portforward.com/networking/staticip.htm

Step 2. Port forward
http://www.portforward.com/english/r...4/Limewire.htm

Step 3. In LW, tools > options > advanced > firewall config. Tick 'manual port forward', add the listening port number to the box here. Apply.