During the Firewall Configuration screen of the Red Hat Enterprise Linux installation, you were given the option to enable a basic firewall as well as to allow specific devices, incoming services, and ports.
After installation, you can change this preference by using the Security Level Configuration Tool.
To start this application, use the following command:
[root@myServer ~] # system-config-securitylevel
Note
The Security Level Configuration Tool only configures a basic firewall. If the system needs more complex rules, refer to Section 43.9, “IPTables” for details on configuring specific iptables rules.