Requiring SSH for Remote Connections

For SSH to be truly effective in protecting your network connections, you must stop using all insecure connection protocols, such as telnet and rsh. Otherwise, a user's password may be protected using ssh for one log in only to be captured when they log in again using telnet.

To disable insecure connection methods to your system, use the command line program chkconfig, the ncurses-based program ntsysv, or the graphical application serviceconf. All of these tools require root access.

Some services to disable include:

For more information on runlevels and configuring services with chkconfig, ntsysv, and serviceconf, refer to the chapter titled Controlling Access to Services in the Official Red Hat Linux Customization Guide.