Enter the tab (Skype) Port Connection (free from Trojan ) for example 54937 and uncheck possibility of connecting to ports 80 and 443
Rule:
1.Allow-UDP-In
any, any, Privileged Ports (check Exclude), single port (54937)
2.Allow-TCP-Out
any, any, Privileged Ports (check Exclude), single port (443)
3.Block-IP-In/Out
any, any, any