Skype Boom Stimulates Reactions from IT Enterprises

The rate at which Skype is growing left many IT managers in some very decisive situations, they no longer have to sit on the fence; those that want to continue using it should bring it in-house to fully manage and control the application and those that don't need to figure out how to block its use outright.

It is crystal clear many advantages Skype has to offer them among which is the provision of cheap long-distance calling, particularly for those who frequently travel abroad. Skype also enables quick collaboration via conferencing for small groups. Best of all, it's easy to use and has a broad user base.

Little wonder Michael Jackson, Skype's vice president of mobile and telecom services, announced at the European IT Forum Sept. 25-26, that Skype has 113 million registered users, 30 percent of which use Skype for business.

By its nature, Skype wants to be on the network and wants to work under any network conditions. The Skype protocol is so well-engineered that it can't be denied access by simply blocking users' access to foreign IP address blocks or to network protocols. Skype also will readily leak out of the network, using high-numbered ports—either TCP or UDP (User Datagram Protocol). As a last resort, it will use ports 80 and 443, which are most commonly used for Web traffic.

Another interesting point is that a firewall that blocks inbound traffic or uses NAT (Network Address Translation) also won't stop Skype. When a Skype client starts, it opens a session with a supernode in the Skype network. If the client cannot be contacted from the Internet, the supernode will notify the client when a call comes in—via the open connection. If the recipient cannot directly contact the sender, the supernode or a relay agent can then act as a proxy between the two callers.

These supernode proxies can be located anywhere on the Internet. In Section 4 of Skype's EULA (end-user license agreement), its revealed that Skype can use any user's computer processor and network resources to help facilitate performance. With enough processing power and network bandwidth at its disposal, any Skype client could be a supernode or a relay agent.

Almost all Skype communications are strongly encrypted with AES (Advanced Encryption Standard), and some setup traffic is obfuscated with RC4 encryption, so the proxies cannot decipher any third-party traffic that crosses through. But this encryption also means that network administrators have no insight into what data is contained within the encrypted stream.

Check out the all new Skype 4.0