setting up ssh keys for passwordless login

Owned by Daniel Somers
Aug 22, 2023
1 min read

Users can set up ssh key auth in order to avoid having to type in a password at every ssh login. The process to do this varies from platform to platform, but there are steps common to all.

Step-by-step guide

From a linux or mac workstation:

  1. Generate your ssh keypair by entering 'ssh-keygen -t rsa' in the terminal. Press enter through the prompts. A passphrase to protect your ssh key is optional . If you opt to use a passphrase, you will have to enter it when authenticating with your ssh key (and some would say this defeats the purpose of using keys for passwordless login). 
  2. Upload your public key to your home directory on DASH by entering 'scp id_rsa.pub <NetID>@dash.duhs.duke.edu:/home/<NetID>' - replace <NetID> with your actual NetID. Never share your ssh private key (id_rsa). 
  3. Log in to DASH via ssh: 'ssh <NetID>@dash.duhs.duke.edu'
  4. Add your workstation's public key info to your authorized_keys file on DASH: 'cat id_rsa.pub >> ~/.ssh/authorized_keys' . If you get an error that this file does not exist, create the needed ~/.ssh content by following the same 'ssh-keygen' steps you followed to generate keys on your workstation, then repeat the 'cat' step.
  5. After saving your modified ~/.ssh/authorized_keys file, exit out of your ssh session and reconnect. On reconnect you should not be prompted for your password (unless you opted to use a passphrase for your ssh key).

The same basic processes apply when using a Windows workstation, but will vary depending upon the ssh client used (putty versus git bash versus Windows Subsystem for Linux, etc).