I have a client providing me with his own id_rsa.pub key, he wants me to setup a SSH server so that he can send me files. As far as I understand, when I setup my SSH Server (freesshd on Windows) I need a private key that will be the fingerprint of my server. Then using the private key provided or generating a new private key, I can generate a public key that I will tie to a user account, allowing my client to use that public key to login without a user/pass combo.
I don't think a server can be configured to use a public key that was not generated from the private key associated with that server.
Am I correct or is there a way to use an existing public key to setup a SSH server if that key was not generated from the private key of said server? Thanks to all!