Skype can use ports other than the default so that it has a “work anywhere” configuration. To set the ports do the following:
* From the “File” menu select “Options”
* Select the “Connection” tab
* Change the port to 443
* Select the box for “Use port 80 as an alternative for incoming connections”
This will set Skype to use two well known ports, 80 HTTP and 443 HTTPS which are open in virtually all environments.