Generate SSH Key Pair

Using SSH keys allows greater security than a password when remoting into a machine, using SFTP, or WP CLI on a remote machine – however, they do require more work to setup.

For security reasons, I generate a new key pair for each site I work on. To generate a new key pair I do the following.

$ cd ~/.ssh
$ ssh-keygen -t rsa -b 4096 -f sal-example-site-rsa -N "my passphrase is sal is awesome" -C sal@example.com

Note: Replace:

• “example-site” with the actual site name
• “my passphrase is sal is awesome” with a randomly generated phrase
• “sal@example.com” with the relevant email address

This creates two new files:

• sal-example-site-rsa
• sal-example-site-rsa.pub

Putting the Files in Place

Quick Way

You can quickly copy your SSH key to the remote server with the following command

ssh-copy-id myuser@example.com -i ~/.ssh/sal-example-site-rsa

Long Way

Alternatively, you can copy your file to the server the long way. After creating these files, on the remote server I create a ~/.ssh directory if one doesn’t exist. (e.g. by SSHing into the account and trying cd ~/.ssh and if that fails (mkdir ~/.ssh).

Then I upload sal-example-site-rsa.pub into the new directory renaming it to authorized_keys.

If ~/.ssh/authorized_keys already exists on the server, I append my new key.

Now I can SSH in without using my password, e.g.

ssh myuser@example.com -i ~/.ssh/sal-example-site-rsa

ssh shortcut

We can reduce this further by using the ~/.ssh/config file.

By adding the following to the end of the file

Host example
  HostName example.com
  User myuser
  IdentityFile ~/.ssh/sal-example-site-rsa

I can now SSH in with

ssh example

Sal Ferrarello (@salcode)

Sal is a PHP developer with a focus on the WordPress platform. He is a conference speaker with a background including Piano Player, Radio DJ, Magician/Juggler, Beach Photographer, and High School Math Teacher. Sal can be found professionally at WebDevStudios, where he works as a senior backend engineer.