RabbitMQ can use multiple ports. This is done to support multiple protocols.
For example, RabbitMQ uses port 5672 to communicate using AMQP (Advanced Message Queuing Protocol). However, RabbitMQ can also be accessed by a web client or RESTful API via HTTP (HyperText Transfer Protocol). In this case, port 15672 is used.
RabbitMQ may also be used for clustered environments. In this case, port 4369 is used to connect to the Erlang Distribution Port Mapper Daemon (epmd).
