Configuring PuTTY for Secure Shell Access
June 20, 2016
PuTTY is a free software package for Windows that implements
the SSH network protocol for establishing an encrypted session with a remote
system. PuTTY provides the client side of a session—it is a console or shell
view of the remote system, much like an MS-DOS command prompt window or the
system view from a mainframe workstation.
When you attempt to establish a session using PuTTY, the remote system
prompts for authentication. This document describes how to configure PuTTY
to use a public/private key pair to authenticate to a remote system.
- You must have at least PuTTY and PuTTYgen installed on your system. You
can download these programs from the
Follow these steps to generate an SSH2 RSA public key:
puttygen.exe to display the Putty Key Generator window.
- Select the SSH2 RSA option in the Parameters section at
the bottom of the window.
- Click the Generate button.
- Move your mouse in the window to generate random information for the key
generator. As you move your mouse, the progress bar proceeds to the right.
When enough random information has been generated, the key generator displays
a public key.
- Type a passphrase into the Key passphrase and Confirm
passphrase boxes. The passphrases must be identical and they should
be unknown phrases--using at least 5 random, unrelated words is recommended.
- Click the Save public key button to save the public key.
Save this file in a location where you will not accidentally delete it.
- Click the Save private key button to save the private key.
Save this file in a location where you will not accidentally delete it and
it is not accessible by others (i.e., do not save it on a shared folder).
- Copy the information in the Public key for pasting into
OpenSSH authorized_keys file box and paste it
into an e-mail message. Send this to the MOREnet system administrator you
have been working with for SSH access. If you have not been working with a
system administrator, please contact MOREnet Technical Support.
Important: Do NOT send the public key
you saved earlier. You must cut and paste the key from the
top of the section labeled Public key for pasting into
OpenSSH authorized_keys file as shown in the figure below:
A PuTTY session is similar to a profile in other programs—it stores important
information about a specific configuration. Follow these steps to configure
putty.exe to display the Putty Configuration window.
- Click Session in the Category section on the left side of
- Type the Host Name provided by the System Administrator.
- Select the SSH option and ensure that the
is set to 22.
- Click SSH in the Category section on the left side of the
- Select the 2 only option in the Preferred SSH protocol
- Click Auth (below SSH) in the Category
- Click Browse... and select the private key file that you
- Click Session at the top of the Category section.
- Type a name in the Saved Sessions box and click Save.
To help you remember the session, you may want to name it the same as the name
you typed in the Host Name (or IP address) box.
- Click Open to initiate a remote session. You will be prompted
about a new server key if it is your first session with the host.
- When prompted, type your login name. This is the name provided to you by
the system administrator.
- If you entered a private passphrase, then when prompted, type the passphrase that you specified for your key.
Upon successful login, PuTTY displays a command line within the secure