Most site administrators use firewalls to protect their network from eventual abuse. Quite often such firewalls do not allow outbound connections to unknown and unused ports, including Jabber client connection port 5222/tcp, which makes it impossible to use Jabber services from inside such firewalls.

JOH provides a way to overcome this difficulty. Its name stands for Jabber Over HTTP. The package provides an easy to use proxy server for Jabber connections. Two proxying methods are supported: HTTP Polling and HTTP CONNECT.

It is intended for use by system administrators who wish to provide access to their Jabber serves via HTTP for those users who happen to be behind strict firewalls.