Password less SSH login to another server can be very useful when
you want to configure a remote backup server or when migrating servers.
For enabling this you need to have openSSH installed on the server.
Here is a tutorial on how to configure password less SSH login to
server ‘mars’ from server ‘earth’
1. Login to earth as root.
2. Run the command ssh-keygen -t rsa
If the key already exists you can either go to step 3 or you can
generate a new key by overwriting existing key (see image). It would be
better to overwrite the existing key if you did not generate it.
3. Change directory to /root/.ssh/
root@earth:~# cd /root/.ssh/
4. Copy the contents of the file id_rsa.pub to the directory /root/.ssh/authorized_keys
5. You will be able to login to the remote server ‘mars’ by typing ssh root@mars_server_IP -p
without password now
Creating Sudo user to login as root:
1. Login to server as root
2. Create a new user by using the command
root@server:~# useradd user
3. Assign a password for the user by using the command
root@server:~# passwd user
4. Add the user to the admin group in /etc/groups
root@server:~# vi /etc/groups