For each cluster, you can specify the port used for cluster communication. The default cluster port number is 7023, and is automatically assigned when the cluster is created. You might need to modify this value if there is a port conflict. See Section 8.12, Viewing or Modifying the Cluster Master IP Address or Port.
If you enable Email Notification, Cluster Services uses Postfix to send messages. The default port number is 25. For information about how to address port conflicts, see Section 8.6.1, Configuring an Email Port.
You must specify the eDirectory port when you install clusters. Port 636 is the default port number for eDirectory communications in the tree.
If you are using a firewall, the port must be opened for CIMOM communications between the cluster and iManager. Port 5989 is the default setting for secure HTTP (HTTPS) communications.