Language Support Selection - Red Hat ENTERPRISE LINUX 3 - INSTALLATION GUIDE FOR IBM S-390 AND IBM ESERVER ZSERIES Installation Manual

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SSH
Secure SHell (SSH) is a suite of tools for logging in to and executing commands on a remote
machine. If you plan to use SSH tools to access your machine through a firewall, enable this op-
tion. You need to have the
remotely, using SSH tools.
Telnet
Telnet is a protocol for logging in to remote machines. Telnet communications are unencrypted
and provide no security from network snooping. Allowing incoming Telnet access is not recom-
mended. To allow inbound Telnet access, you must install the
Mail (SMTP)
If you want to allow incoming mail delivery through your firewall, so that remote hosts can
connect directly to your machine to deliver mail, enable this option. You do not need to enable
this if you collect your mail from your ISP's server using POP3 or IMAP, or if you use a tool such
as . Note that an improperly configured SMTP server can allow remote machines to
fetchmail
use your server to send spam.
You can allow access to ports which are not listed here by listing them in the Other ports field. Use
the following format: port:protocol. For example, if you want to allow IMAP access through
your firewall, you can specify imap:tcp. You can also explicitly specify numeric ports; to allow
UDP packets on port 1234 through the firewall, enter 1234:udp. To specify multiple ports, separate
them with commas.
Finally, select any devices should allow access to your system for all traffic from that device.
Selecting any of these trusted devices excludes them from the firewall rules. For example, if you are
using eth0 as a local networking device and using eth1 to connect to the Internet, any traffic coming
from your local network is allowed. Selecting eth0 as trusted means all traffic over the Ethernet is
allowed, but the eth1 interface is still firewalled. If you want to restrict traffic on an interface, leave it
unchecked.
It is not recommended that you make any device that is connected to public networks, such as the
Internet, a trusted device.
Tip
To change your security level configuration after you have completed the installation, use the Security
Level Configuration Tool.
Type the
redhat-config-securitylevel
Configuration Tool. If you are not root, it prompts you for the root password to continue.

2.15. Language Support Selection

You can install and support multiple languages for use on your system.
You must select a language to use as the default language. The default language is the language used
on the system once the installation is complete. If you choose to install other languages during this
installation, you can change your default language after the installation.
If you are only going to use one language on your system, selecting only that language saves signifi-
cant disk space. The default language is the language you selected to use during the installation.
Chapter 2. Installing Red Hat Enterprise Linux
package installed in order to access your machine
openssh-server
command in a shell prompt to launch the Security Level
package.
telnet-server