[ Thanks to Andrew
Weber for this link. ]
“The firewall configuration no longer has the SELinux settings
and it will take you through a number of steps to set up the
firewall. Of course you will want to enable the firewall and then
select “Customize” with the tab.“Use the space key to select the services to enable. The list is
greatly expanded in the version for CentOS 6. The name that is used
is coming from the file /etc/services which is a system file that
connects a name with the port. So if you are wondering which port
is being referenced you may review that file.”