Best way to use multiple SSH private keys on one client [closed]

Question

I want to use multiple private keys to connect to different servers or different portions of the same server (my uses are system administration of server, administration of Git, and normal Git usage within the same server). I tried simply stacking the keys in the id_rsa files to no avail.

Apparently a straightforward way to do this is to use the command

ssh -i <key location> [email protected]  

That is quite cumbersome.

Any suggestions as to how to go about doing this a bit easier?

Answer 1

You can instruct ssh to try multiple keys in succession when connecting. Here's how:

$ cat ~/.ssh/config IdentityFile ~/.ssh/id_rsa IdentityFile ~/.ssh/id_rsa_old IdentityFile ~/.ssh/id_ed25519 # ... and so on  $ ssh server.example.com -v .... debug1: Next authentication method: publickey debug1: Trying private key: /home/example/.ssh/id_rsa debug1: read PEM private key done: type RSA debug1: Authentications that can continue: publickey debug1: Trying private key: /home/example/.ssh/id_rsa_old debug1: read PEM private key done: type RSA .... [server ~]$ 

This way you don't have to specify what key works with which server. It'll just use the first working key.

Also you would only enter a passphrase if a given server is willing to accept the key. As seen above ssh didn't try to ask for a password for .ssh/id_rsa even if it had one.

Surely it doesn't outbeat a per-server configuration as in other answers, but at least you won't have to add a configuration for all and every server you connect to!

Answer 2

From my .ssh/config:

Host myshortname realname.example.com     HostName realname.example.com     IdentityFile ~/.ssh/realname_rsa # private key for realname     User remoteusername  Host myother realname2.example.org     HostName realname2.example.org     IdentityFile ~/.ssh/realname2_rsa  # different private key for realname2     User remoteusername 

Then you can use the following to connect:

ssh myshortname

ssh myother

And so on.