Step # 1: Generate first ssh key
Type the following command to generate your first public and private key on a local workstation. Next provide the required input or accept the defaults. Please do not change the filename and directory location.
workstation#1 $ ssh-keygen -t rsa
Finally, copy your public key to your remote server using scp
workstation#1 $ scp ~/.ssh/id_rsa.pub user@remote.server.com:.ssh/authorized_keys
Step # 2: Generate next/multiple ssh key
a) Login to 2nd workstation
b) Download original the authorized_keys file from remote server using scp
workstation#2 $ scp user@remote.server.com:.ssh/authorized_keys ~/.ssh
c) Now create the new pub/private key:
workstation#2 $ ssh-keygen -t rsa
d) Now you have new public key. APPEND this key to the downloaded authorized_keys file using cat command:
workstation#2 $ cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
workstation#2 $ scp ~/.ssh/authorized_keys user@remote.server.com:.ssh/
You can repeat step #2 for each user or workstations for remote server.
Step #3: Test your setup
Now try to login from Workstation #1, #2 and so on to remote server. You should not be asked for a password: