Include domain along with username in PuTTY

I've seen this happen when the user's home directory isn't local, but on an NFS automount on the network. If your home directory isn't already mounted when sshd goes to look for your ~/.ssh/authorized_keys, it won't be able to access it in time, so public-key-based authentication will fail.

The first thing you need is a key that PuTTY can understand. PuTTY requires a .ppk file, which is not the same as the standard openSSH key file. You can use the PuTTYgen tool to generate a key or to convert an existing openSSH to a putty key.

Once you have a key, you need to tell PuTTY about it. For this you have two options:

• Specifiy a key directly
• Use Pageant to store keys

Once you have PuTTY all setup, you need to make sure you have added your public key to the authorized_keys file. Once that is all setup you should be able to connect.