Kerika lets you connect with your friends and colleagues across the world:

That's because we use JXTA, an open-source peer-to-peer technology that helps you hook up with other Kerika users even when you are hidden behind a firewall.

Here's how it works: whenever you start up Kerika, your computer automatically tries to contact a rendezvous server located at Kerika's data center. The rendezvous server acts as a kind of matchmaker: it tells your computer how to get in touch directly with other Kerika users are online. At the same time, your computer tells the rendezvous server know how you can be reached. (Learn more about how peer-to-peer networks work.)

Most of the time this works just fine, especially if you are at home or in a wireless hotspot like a coffee shop. But there may be times when your computer is deliberately hidden from the outside world, for example, when you are sitting behind a firewall at work that stops your computer from contacting the rendezvous server directly. Kerika uses ports 10421 and 10422 on your computer to reach the rendezvous server, and these ports may be blocked by the firewall. And there may be nothing you can do about it if your corporate IT folks simply refuse to open the ports for Kerika to work.

That's when the relay server at Kerika's data center kicks in: it helps you talk to the rendezvous server by using port 80 on your computer, which is always open because that's what your browser uses to access the Web.

So if you are working at a company with a locked-down firewall, you can still hook up with other Kerika users worldwide!