I'm trying to set up ssh keys and I don't do this often. That said, I have 3-4 key pairs in my .ssh/ dir already. WHen I do ssh firstname.lastname@example.org how does ssh know what key to use?
I don't want to have key per site, but rather use one private key for lots of sites, and put the public key on the remote server. Sometimes my username on the server is not the same as my local username (often). How does SSH know which key I want to use?