1.
OSX Firewall settings for Tiger though many mac users have their firewalls turned off. I turn it on & off intermittently depending upon sites I visit.
2. For your Billion, make sure UPnP is enabled,
http://www.portforward.com/routers.htm for details of how to log in. For setting up UPnP, see UPnP section, under Billion heading here
http://www.gnutellaforums.com/showth...threadid=51357