When you install Broker Server or create a new Broker Server with the server_config utility, you specify the server's base port. Broker Server uses the base port for non-SSL communications. It uses the two ports immediately below the base port for SSL-based communications.

By default, port 6849 is the Broker Server base port. If you do not explicitly assign a base port when you install or create a Broker Server, it uses the default port 6849 for non-SSL requests, ports 6848 and 6847 for SSL requests, and 6846 and 6845 for parallel channels.