So how can you get multiple users in your office use skype, without using up 100+ TCP connections going per client simultaneously?
Despite setting Skype to go through your company’s Proxy, Skype will still try and see if it can be sneaky and connect directly anyway. So instead you will have to give it no choice, but to go through your firewall (or proxy strictly speaking). In our case, I’ve set our firewall/proxy to only allow predefined outgoing ports such as 80, 443 (HTTP/s), FTP (21), SMPT/POP3 (25/110). You network will continue to run, as web-browsing, and emailing is allowed, but all other outgoing traffic is blocked. It’s a pretty good idea, as this will inadvertently help blocking out malware/spyware/trojan connections should any computer on your network be affected. Now set Skype (Tools -> Options -> Advanced -> Connections ) to go through your Firewall proxy server. Type in all the relevant settings, restart Skype and see what happens.
At first nothing. Absolutely nothing. For about one minute. Go on, check your firewall logs and watch how Skype learns to behave.
As Skype tries to connect directly, your firewall ignores the connection attempts, and finally Skype falls back to try and use the settings you entered! Nicely pottering along with no more than two to three TCP connections, you have all the connectivity you need for high quality video calls and chats, and still enough bandwidth for all your other network needs.
A few thoughts, if your firewall doesn’t have or use a Proxy. Privoxy is a free and easy to use Proxy Server.
