How can i add a SSH to a Single server


Hello all,

We have our own SSH setup in the Controlpanel no problem, but now a user wants to connect thru SSH to a particular server, so we need to add his SSH key to one single server.

How do i do that, every where i read how to add them to the SSH section of the controlpanel but i do not want them to have access to amm our serverS, when i add it directly to authorized_keys it will be overwritten on the next boot i suppose?

anyone a tutorial ?