Avaya recommends the CMS and CMS Supervisor clients to remain behind a firewall for protection from the Internet.

For more information about which ports are open or closed by default, see Port Matrix for Avaya Call Management System.

On RHEL, the firewall is managed through the iptables and ip6tables services. CMS provides a utility to generate the firewall rules and to start and stop the firewall services. The utility is also included in the security option of the cmssvc command. For more information about how to turn on or turn off the firewall, see Maintaining and Troubleshooting Avaya Call Management System.