OS X, SSH: use different private key files for different servers

Question

I want to use different private key files to connect to different SSH servers (ssh://git-server:port/repository). How to manage that? SSH seems to assume the private key file in ~/.ssh/id_rsa.

Answer 1

That's why there's the -i option:

-i identity_file

Selects a file from which the identity (private key) for RSA or DSA authentication is read. The default is ~/.ssh/identity for protocol version 1, and ~/.ssh/id_rsa and ~/.ssh/id_dsa for protocol version 2.

Identity files may also be specified on a per-host basis in the configuration file. It is possible to have multiple -i options (and multiple identities specified in configuration files).

If you want to make this permanent, you need to setup your SSH config file and set the according IdentityFile option.

IdentityFile

Specifies a file from which the user's DSA, ECDSA or DSA authentication identity is read. […]

If you see a dialog similar to this:

You need to enter your user password for your OS X account. Not your key passphrase, or the remote SSH password. This is because they identity hasn't been stored in the keychain.

According to this tutorial, the following command should add them appropriately:

ssh-add -K