How can I save my passphrase for an SSH server in PuTTY?

Solution 1:

You can store the passphrase for your private key, for the current session, using Pageant, PuTTY's SSH agent:

1. Double-click on your .ppk private-key file.
2. Enter the password.
3. Optional: For servers you trust, enable agent forwarding in Connection → SSH → Auth.

But you cannot store the server password itsef:

A.2.8 Does PuTTY have the ability to remember my password so I don't have to type it every time?

No, it doesn't.

(snip)

In SSH, remembering your password would be possible in theory, but there doesn't seem to be much point since SSH supports public key authentication, which is more flexible and more secure. See chapter 8 in the documentation for a full discussion of public key authentication.

(See also PuTTY wishlist: remember-password)

On Windows, I have my private key passwordless but encrypted using the EFS, so it can be loaded at startup automatically but only if I log in with my password. (Previously I had it in a TrueCrypt volume, with that volume's keyfile on an USB drive. Don't ask me which is more secure, if at all.)

Solution 2:

You cannot store the passphrase for your private key permanently using Pagent, PuTTY's SSH key agent. You will have to store it unencrypted if you wish to avoid retyping the passphrase again and agian.

I suggest protecting all your keys with one standard easy to type passphrase.