Chapter 3. Installing Red Hat Linux

59

Telnet

Telnet is a protocol for logging into remote machines. Telnet communications are unen 

crypted and provide no security from network snooping. Allowing incoming Telnet access

is not recommended. If you do want to allow inbound Telnet access, you will need to install

the

telnet server

package.

WWW (HTTP)

The HTTP protocol is used by Apache (and by other Web servers) to serve webpages. If

you plan on making your Web server publicly available, enable this option. This option is

not required for viewing pages locally or for developing webpages. You will need to install

the

httpd

package if you want to serve webpages.

Enabling WWW (HTTP) will not open a port for HTTPS. To enable HTTPS, specify it in

the Other ports field.

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

fetchmail

. Note that an improperly configured SMTP server can allow

remote machines to use your server to send spam.

FTP

The FTP protocol is used to transfer files between machines on a network. If you plan on

making your FTP server publicly available, enable this option. You need to install the

wu 

ftpd

(and possibly the

anonftp

) package for this option to be useful.

Other ports

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 explic 

itly specify numeric ports; to allow UDP packets on port 1234 through the firewall, enter

1234:udp. To specify multiple ports, separate them with commas.

Tip

To change your security level configuration after you have completed the installation, use the Security

Level Configuration Tool.

Type the redhat config securitylevel command in a shell prompt to launch the Security Level

Configuration Tool. If you are not root, it will prompt you for the root password to continue.

3.23. Language Support Selection

Red Hat Linux 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 will be 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 will save

significant disk space. The default language is the language you selected to use during the installation.