HOW TO: Block Skype On A Corporate Network
Source: voipcentral.org
Some countries are moving to block Skype on corporate networks as some see it as a security vunerability. A systems administrator from the United Arab Emirates has come up with a simple method to block the popular net telephony program. So if it is blocked on your network this might be how it was done.
How it is done
The choice of OS to run the proxy on is subjective (I chose OpenBSD as my network OS of choice for its proven security
record and excellent reliability) and has no effect over the actual blocking mechanism. The same can be accomplished on any other BSD or Linux flavour…As mentioned above, blocking SSL or the ‘Connect’ method, means blocking access to all legitimate websites that use SSL (Hotmail, Yahoo, E-banking, E-commerce websites, e.g any website that is secured by SSL). Should you go down that road, you would have to explicitly allow all permitted destinations (an ongoing technical nightmare).
The catch in successfully blocking Skype given all of the above, would be to block access to requests made by clients, to destination specified by their numeric IP address, AND using the ‘Connect’ method to tunnel the Skype
data.
