Kerika lets you connect with your friends and colleagues, no matter where you are: at home, at work, on campus or in a coffee shop. 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 using ports 10421 and 10422.

But if you are working behind a corporate firewall, your IT administrator may have closed these ports. If your computer cannot use ports 10421 and 10422, Kerika will automatically try to connect to Kerika's relay server instead, using port 80.

Port 80 is very likely to be open on your network, regardless of where you are, because this port is used by your Web browser, and if this port were also closed, you really wouldn't have much Internet connectivity at all! The picture below shows how the relay server helps people who are hidden behind firewalls:

• First, the relay server helps you hook up with the rendezvous server, so that you can check in and let other Kerika users know that you are online.


• Next, the relay server checks with the storage server to see whether there are any messages or files waiting for you – maybe some of your buddies sent you stuff while you were offline, and these messages are waiting there for you, just like email waiting on an email server.


• The relay server also acts as an intermediary between you and other Kerika users who are online: since you are behind a firewall, other Kerika users cannot directly contact you, so they send messages intended for you to the relay server which forwards them on to you

The best part about all this is that Kerika takes care of all this plumbing -- you don't have to worry about where you are when you fire up Kerika, or where your buddies are, or even whether they are online!

Want to learn more?

• Read a whitepaper on JXTA (PDF document will open in new window)