SSH keys are a means of authenticating a user to an SSH server without using a password. Each “key” is actually a key pair consisting of a public key and a private key. Keys are more secure than passwords because they are significantly more complex.
There are many options of running the SSH on Macs, however we recommend running this from the terminal command line as this is the easiest. To get started, you need to open the Terminal application which is found in Applications Utilities Directory, but you can also launch this by hitting cmd+spacebar and typing “Terminal” into the search box and then return. How to use PuTTY SSH keys with the built-in OpenSSH. If you have a PuTTY.ppk format private key and want to use it with the built-in OpenSSH on Mac on the command line or in scripts, you can use the following commands. First, install PuTTY for Mac using brew install putty or port install putty (see below). If these files exist, then you have already created SSH keys. You can overwrite the keys with the following commands, or skip this step and go to configuring SSH keys to reuse these keys. Create your SSH keys with the ssh-keygen command from the bash prompt. This command will create a 2048-bit RSA key for use with SSH. For more background and examples, see Detailed steps to create SSH key pairs. For additional ways to generate and use SSH keys on a Windows computer, see How to use SSH keys with Windows on Azure. Supported SSH key formats. Azure currently supports SSH protocol 2 (SSH-2) RSA public-private key pairs with a minimum length of 2048 bits. So far in this series of posts on ssh on macOS. Quick Introduction to ssh for Mac Admins; SSH Keys, Part 1: Host Verification; SSH Keys, Part 2: Client Verification; Transferring files with ssh (this post); SSH Tunnels (upcoming); Please consider supporting Scripting OS X by buying one of my books! In the previous posts we looked how to connect with ssh to a remote computer (host) and how to.
While a password of eight characters is 72 bits long, SSH keys are often 2048 bits or longer. This longer string has many more possible permutations and therefore takes much more time to crack with a brute force attack.
If you require SSH access for multiple users, the use of SSH keys instead of individual logins can bypass many of the headaches involved in user management without violating PCI DSS. See What are the advantages of using SSH keys to control access for multiple users? for details.
Method
The process involves generating a pair of SSH key files containing a private key and a public key. The private key is known only to the user’s computer; the public key will be known to the server. Each key is useless without the other; therefore, only individuals with both the private and the public key can gain access to the server, and the private key is never revealed to the server.
Users should take special care to not lose the private key. A lost private key cannot be replicated; therefore, the user cannot access the server until an administrator generates a new key pair. If you lose access to your server due to a lost key, contact our Support Team for assistance.
1: Create and save the SSH key files
- Issue the ssh-keygencommand; see the example below:
- The keys save to the default location or, if one was specified, in a separate file. Choose one:
- If you do want a passphrase, type it now and hit Enter. Type the passphrase again when prompted.
- If you do not want a passphrase, hit Enter twice in succession without entering a passphrase.
- If you do want a passphrase, type it now and hit Enter. Type the passphrase again when prompted.
- You will now see the identification fingerprint for the SSH key. This image is automatically generated.
2: Transfer the public key file to the receiving server
- If you are a Nexcess Cloud client, log in to your Client Portal to add the key. If you cannot find your login credentials, either click Forgot Password? on the login page, or contact our 24/7 support team.
- If you are not a Nexcess Cloud client, the easiest method-of-transfer uses the ssh-copy-id command. Run the ssh-copy-idcommand with the same arguments used for connecting to the server using the sshcommand:
3:Test the connection
- Issue the following command:
- Select Yes to accept the key fingerprint.
- Attempt to log in to the server. If ssh key authentication is functioning properly, you will log in successfully.
- If prompted, type the passphrase created in 1: Create and save the SSH key files.
View Ssh Key Mac
For 24-hour assistance any day of the year, contact our support team by email or through your Client Portal.
First cool thing that everybody knows already: Mac OSX is based on Unix so you get ssh out of the box.
Second cool thing you may not know: OS X 10.5 actually also comes with an ssh key agent (ssh-agent). That means that, without any additional software (like PuTTY Agent on Windows...), Mac OSX can actually load an encrypted private key into memory and remember it for all subsequent connections...
Third cool thing that almost seems too good to be true: ssh-agent can store the passwords of the encrypted keys into your keychain. Than means that you have to tell it once to remember the decryption password for your key(s) like this:
ssh-add -K .ssh/id_whatever_your_rivate_key_is
And next time you log into your mac and try to ssh somewhere, your private key will be loaded automagically (as long as your keychain is unlocked of course).
Very groovy!!
Get Ssh Key Mac
This entry was posted on Dec 21 2008 at 02:34 by admin and is filed under Linux stuff, Mac stuff. Tags: howto, mac os x, ssh, terminal