SSH Key based authentication

It seems like I'm always connecting to servers via ssh and I hate having to remember my password. I remember a long time ago someone showed me how to place your public key on the server so you could log in automatically but then I forgot how to do it. Well thats what this BLOG is for - here are the steps to doing it.

• Generate the Keys
• Copy your public key to the server and visa versa
• Connect and authorize

• Generate the Keys
All you need to do this is enter ssh-keygen into the terminal and you will be taken through a few steps.

#1 It will ask you where you want to save it. The default is in /Users/yourname/.ssh/id_rsa. Just stick with that.

#2 It will ask if you would like to add a passphrase to the key or leave it empty - enter a password that you can easily remember - you will need to enter the password twice. After you enter the passphrase it will display the key's randomart image.

• Copy your public key to the server
Now that the keys have been created you need to move the public one to the server. Navigate to the ~/.ssh directory and inside there you will find something like this:

-rw------- 1 user staff 1743 Jan 21 21:09 id_rsa
-rw-r--r-- 1 root staff 416 Jan 21 21:09 id_rsa.pub
-rw-r--r-- 1 user staff 4252 Jan 11 22:19 known_hosts

The file you want is the id_rsa.pub file so go ahead and do a "more" on that and copy the contents to the clipboard. Now go to the server you want to add this to and log in FOR THE LAST TIME (HA!) and navigate to the ~/.ssh and touch a file and name it "authorized_keys". Then do a chmod 644 ~/.ssh/authorized_keys. After thats complete do a sudo pico authorized_keys and paste in the key info you copied to your clipboard.

• Copy your server key to you:
Same process, go to the server and do this:
1. ssh-keygen - save it to the defaut location, enter a password
2. create the authorized_keys file, chmod 644
3. pico and paste the key from YOUR machine's id_rsa.pub file

Now you have the key from the server in your authorized_keys file and the server has your key in it's authorized_keys.

• Connect and authorize
Now that the key is in both places all you need to do is log out and log back in. Once you connect from your machine to the server you will see a pop up window (in the OS, not in the terminal) that asks you to authorize the connection with your public key (the password that you entered in when you created the key) and once you do this you will have completed the handshake and never again will you need to enter a password for this server.

It's just that easy! Enjoy.