Hello we have 80+ users and a Firebox 700 firewall. Since we blocked other im softwares, users have begun to use Skype. I cannot block Skype in port level because it uses port 443 and 80 if it doesnt connect from other ports. but as you know, it is impossible to block these ports. I can block remote server addresses of Skype but Skype changes their server addresses almost every day. And program always finds an avalaible server that we didnt know its address before. I searched on the web to find a solution but all suggestions i have applied didnt work. Any suggestion to block Skype forever? For example Application signature? But i dont know if Watchguard supoorts application signature protocol and if it does, how can i do this. Please help