SSH to Use Public Key Authentication

SSH to Use Public Key Authentication



1. At the shell prompt of the client system



ssh-keygen –t rsa




or



ssh-keygen –t dsa





2. When prompted for the file in which the private key will be saved,
press enter to use the default filename of



~/.ssh/id_rsa 



or



~/.ssh/id_dsa




The associated public key will be saved as




~/.ssh/id_rsa.pub 



or



~/.ssh/id_dsa.pub






The next thing you need to do is to copy the public key you just
created to the SSH server. 




scp ~/.ssh/key_name.pub   user_name@address_of_SSH_server:filename






At this point, the contents of the key file you just copied need to be
appended to the end of the 





~/.ssh/authorized_keys 




file in the home directory of the user you will connect to the SSH server as.







If desired, you can use the



ssh-agent 



command to eliminate the need to enter the passphrase every time you establish 
an SSH connection.





1. At the shell prompt of your client system, enter



ssh-agent bash


2. At the shell prompt, enter




   ssh-add ~/.ssh/id_rsa 




   or




   ssh-add ~/.ssh/id_dsa






   depending on which key file you have created.




3. When prompted, enter the key file’s passphrase. When you do, you
   should be prompted that the identity has been added. An example
   follows:



      rtracy@ws1:~> ssh-agent bash
      rtracy@ws1:~> ssh-add ~/.ssh/id_rsa
      Enter passphrase for /home/rtracy/.ssh/id_rsa:
      Identity added: /home/rtracy/.ssh/id_rsa (/home/rtracy/.ssh/id_rsa)
      rtracy@ws1:~>






    Once this is done, the ssh-agent process stores the passphrase in
    memory. It then listens for SSH requests and automatically provides
    the key passphrase for you when requested.





Encryption V