Other Ports; Saving The Settings; Activating The Iptables Service - Red Hat ENTERPRISE LINUX 4 System Administration Manual

or IMAP, or if you use a tool such as fetchmail. To allow delivery of mail to your machine, select
this check box. Note that an improperly configured SMTP server can allow remote machines to
use your server to send spam.
NFS4
The Network File System (NFS) is a file sharing protocol commonly used on *NIX systems.
Version 4 of this protocol is more secure than its predecessors. If you want to share files or
directories on your system with other network users, select this check box.
Samba
Samba is an implementation of Microsoft's proprietary SMB networking protocol. If you need to
share files, directories, or locally-connected printers with Microsoft Windows machines, select this
check box.

18.2.4. Other Ports

The Security Level Configuration Tool includes an Other ports section for specifying custom IP
ports as being trusted by iptables. For example, to allow IRC and Internet printing protocol (IPP) to
pass through the firewall, add the following to the Other ports section:
194:tcp,631:tcp

18.2.5. Saving the Settings

Click OK to save the changes and enable or disable the firewall. If Enable firewall was selected,
the options selected are translated to iptables commands and written to the /etc/sysconfig/
iptables file. The iptables service is also started so that the firewall is activated immediately after
saving the selected options. If Disable firewall was selected, the /etc/sysconfig/iptables file is
removed and the iptables service is stopped immediately.
The selected options are also written to the /etc/sysconfig/system-config-selinux file so
that the settings can be restored the next time the application is started. Do not edit this file by hand.
Even though the firewall is activated immediately, the iptables service is not configured to start
automatically at boot time. Refer to
information.

18.2.6. Activating the IPTables Service

The firewall rules are only active if the iptables service is running. To manually start the service, use
the following command:
[root@myServer ~] # service iptables restart
To ensure that iptables starts when the system is booted, use the following command:
[root@myServer ~] # chkconfig --level 345 iptables on
The ipchains service is not included in Red Hat Enterprise Linux. However, if ipchains is installed
(for example, an upgrade was performed and the system had ipchains previously installed),
Section 18.2.6, "Activating the IPTables Service"
Other Ports
for more
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