I am trying to satisfy a weird case, so bear with me please.
I want to use [don't gasp] graphical Windows tools (like WinSCP, PuTTY, etc) with signed OpenSSH keys. These tools don't support signed keys. But they do support a whole lot of "forwarding" and "proxy" methods.
I can set them up with a "local proxy" that actually executes OpenSSH command with the signed keys to the same server and setups up a tunnel: local port
2222 forwards to server's
Great, now the Windows tools can execute
ssh/scp commands over the already-authenticated tunnel... but the first thing they try to do is: open ssh and authenticate (and they can't pass a signed key...).
So, since I already authenticated on the tunnel, can I configure the remote machine's ssh server to NOT ask nor for password, nor key, if the connection attempt is done over 127.0.0.1:22?
Please note I am not talking about a "jump" server to reach "remote". I only have 1 "remote" server.
On my Ubuntu server, I want to do
ssh email@example.com and not be asked for key or password, but only if request came from 127.0.0.1