ssh - for Secure Shell - is a secure alternative to telnet and rlogin. Most modern Linux distributions will simply forbid you to run a telnet server anyway.
First create a user to be used when logging in over ssh
adduser foobar
If adduser didn't ask for a password, add that with
passwd foobar
This is important as some people will scream blood and murder if they see you connecting as root using ssh.
To install ssh do this:
- Debian - apt-get install ssh
- Gentoo - ssh is already there, edit /etc/ssh/sshd_config
- Fedora - ssh is already there and working
The rest of this text will be for Debian Etch 4.0, as that is the distribution I use. I'm sure a lot of the commands will work in other distributions as well though
OpenSSH should be running after issuing apt-get install ssh. To check this run
ps -ef | grep ssh
The output should look similar to this if everything is working
root 764 1 0 10:51 ? 00:00:00 /usr/sbin/sshd root 778 519 0 11:02 tty1 00:00:00 grep ssh
Now stop root from being able to log in by setting
PermitRootLogin no
in /etc/ssh/sshd_config. The setting is already in the file, but set to yes. After you have edited the sshd_config file you need to restart the ssh deamon
/etc/init.d/sshd restart
If you need to do something with root privileges you can just login using the account you created earlier (foobar) and then use su -. You will be asked for the root password, and then you can do anything root can.
To connect to the ssh daemon you need a ssh client like Putty.