Barrick Lab :: SSH Public Key Authentication

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---+ Setting up SSH Public Key Authentication

These instructions will allow you to connect as *user1* on machine *FROM* to *user2* on machine *TO* without typing your password for the <code>ssh</code> and <code>scp</code> commands. This can be very useful when doing batch copies (e.g. using <code>batch_run.pl</code> to copy many directories of <code>breseq</code> results) or for machines that you constantly find yourself needing to login to.

*Step 1:* Log into machine *FROM* as *user1*. Run the <code>ssh-keygen</code> command. Leave the passphrase empty. (Just hit return when prompted for the passphrase.)

On machine *FROM*:

<div style="border-color: grey; border-style: solid; border-width: 1px; padding:6px;"><verbatim>$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user1/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/user1/.ssh/id_rsa.
Your public key has been saved in /home/user1/.ssh/id_rsa.pub.
The key fingerprint is:
d2:e1:78:ac:c1:13:01:f2:a7:84:94:7d:a6:06:f8:1a lab@backup
The key's randomart image is:
+--[ RSA 2048]----+
| .oo...          |
|..o+. o.         |
| ...o+o .        |
|E ..o+ * .       |
| o .. * S        |
|.      *         |
|      .          |
|                 |
|                 |
+-----------------+</verbatim></div>

*Step 2:* create the ssh directory on machine *TO* as *user2*, if it does not exist:

On machine *TO*:
<div style="border-color: grey; border-style: solid; border-width: 1px; padding:6px;"><verbatim>
$ ssh user2@TO mkdir -p .ssh
user2@TO's password: </verbatim></div>


*Step 3:* Add the key that we just created for *user1* on *FROM* as a new line in the <code>.ssh/authorized_keys</code> file in account *user2* on machine *TO*.

On machine *FROM*:
<div style="border-color: grey; border-style: solid; border-width: 1px; padding:6px;"><verbatim>
$ cat .ssh/id_rsa.pub | ssh user2@TO 'cat >> .ssh/authorized_keys'
user2@TO's password:</verbatim></div> 

To add login to additional remote machines, repeat *Step 3*.
This topic: Lab > WebHome > ProtocolList > ProtocolsSSHPublicKeyAuthentication
Topic revision: r2 - 2016-02-29 - JeffreyBarrick