Introduction:
In the SSH protocol, an access credential is known as an SSH key. It serves a similar purpose as user names and passwords, although system administrators and power users typically use the keys to automate procedures and achieve single sign-on. This is one of the best ways to keep your server secured whilst being able to access it from multiple other VMs.
Let's now focus on how to generate a keypair for Ubuntu 20.04 and then use it to access the host server.
Prerequisites:
- Ubuntu 20.04 installed or an Ubuntu 20.04 server set up.
- User account with admin privileges.
- Second server to access the user account.
- Working knowledge of the Linux command line.
Steps:
- This is the host server that we are trying to access.
- This is the server from which we are trying to access the main server.
Step 1:
- Enter the command ssh-keygen to generate a key pair.
ssh-keygen
Step 2:
- You can now enter a file path or press enter to select default path to save your keypair.
- If you want to overwrite your existing key, press y. This process is not reversable.
- Your keypair’s fingerprint and random art image is now generated.
Step 3:
- Enter the command ‘ssh-copy-id username@remote_host’ or ‘ssh-copy-id root@remote_host’ to get the root access.
ssh-copy-id username@remote_host or ssh-copy-id root@remote_host 
Step 4:
- Enter your host server’s password to continue. Once entered you are now connected.
Step 5:
- Use the command ‘ ssh username@remote_host’ or 'ssh root@remote_host' depending on the acccess you specified to login to the host server.
ssh username@remote_host or ssh root@remote_host
- You are now logged in to your host server.
