Password-less SSH setups save time and hassle. It plays an important role especially when triggering scripts or copying files to a remote machine. Previous posts have outlined a few of the scenarios where the set-up can apply -- for the same account and for establishing trust between distinct accounts.
FAQ: There is another scenario where password-less ssh can apply. This scenario is very typical in support teams, as I have experienced, whereby a system administrator administers machines remotely from his Windows desktop. Can password-less ssh still apply?
Start off by downloading the necessary tools. For this trick to work, you will be needing the following software binaries: putty.exe, puttygen.exe and pscp.exe. The tools mentioned can be downloaded off the author's website. If you have them readily available, let us proceed.
Start off by launching puttygen.exe. This tool will generate the public and private key pairs needed for the password-less setup, similar to ssh-keygen.
Press "Generate" and help the software do its thing. Afterward, save the private and public keys. And when prompted with a warning for empty passphrase, confirm the save. As always, save the private key to a secure location, where only you can access it (as much as possible).
Open putty.exe. Scroll down to Connection --> Data.. fill in the field "Auto-login username". For this example, the username used is "user".
Scroll further down.. Under Connection --> SSH --> Auth. Point it to the path where the private key file was saved. This will be the private key to be used for password-less authentication.
Scroll up to Session, fill up the necessary fields and save.
Open a command tool and with pscp.exe, copy the public key over to the home directory of user. The public key has to be translated to OpenSSH format, then has to be added to authorized_keys file.
user@host:~ > ssh-keygen -i -f PUBLIC_KEY >> $HOME/.ssh/authorized_keys
Go back to putty.exe, load the saved session (double click the saved session) or click Open and see password-less ssh in action.
There you go. Password-less ssh from Windows to your _nix workstation. Give it a go and save yourself the hassle of presenting credentials again and again.
