Question

I couldn’t find any basic info for designers (on a mac) for how SSH keys work – so thought I’d ask them here.

If I want to connect my work workstation to:

• Github
• A DEV server
• A LIVE server

Do I generate one ssh key on the workstation and add it to all those servers or do I generate multiple keys – one for each server?

Once I’ve generated a key (or keys), do I copy it into the id_rsa file in my user account on that server (I realize I may have to create the id_rsa file)?

And if I now want to access the same server but from my home laptop, do I add the laptop’s ssh key to the same id_rsa file on the server or do I create a new file?

If I need to create a new file, does it matter what the file is called – laptop_rsa?

I basically want to disable root login on my servers but I don’t really understand how SSH applies to multiple machines and multiple servers.

Any help or pointers in the right direction would be much appreciated.

Cheers

Answer 1

• You only need one key for the local machine that you are connecting
  to all three servers.

• For the DEV server and the LIVE server, you can add the contents of
  your id_rsa.pub file to the
  authorized_keys file on each of the target servers.
  This file will be in the ~/.ssh directory. You will
  need to create the file if it’s not there (touch
~/.ssh/authorized_keys). Adding your public key to this file
  will let you login with your passphrase rather than a password.

• Place all authorized keys (i.e. your laptops id_rsa.pub) in the same
  authorized_keys file on the target server.

Adding your keys to authorized_keys doesn’t affect root login (that is a separate setting), however, it will prevent people from attempting to brute-force your password if you then turn off password login.