I'm behind a firewall, can I use Jabber?

The standard port for Jabber communication is 5222, so you may need that port open to use Jabber. We have also defined a way to do Jabber over HTTP but it is not yet deployed everywhere. Some Jabber clients enable you to use a "proxy server" if port 5222 is not open. There is also a special IM service called jabber80.com if all else fails.