Cloudera Manager, CDH components, managed services, and third-party components use the ports listed in the tables that follow. Before you deploy Cloudera Manager, CDH, and managed services, and third-party components make sure these ports are open on each system. If you are using a firewall, such as iptables, and cannot open all the listed ports, you must disable the firewall completely to ensure full functionality.
In the tables in the subsections that follow, the Access Requirement column for each port is usually either "Internal" or "External." In this context, "Internal" means that the port is used only for communication among the components (for example the JournalNode ports in an HA configuration); "External" means that the port can be used for either internal or external communication (for example, ports used by NodeManager and the JobHistory Server Web UIs).
Unless otherwise specified, the ports access requirement is unidirectional, meaning that inbound connections to the specified ports must be allowed. In most modern stateful firewalls, it is not necessary to create a separate rule for return traffic on a permitted session.