FYI, this happens because SSH automatically presents a public key to the server when trying to authenticate. If the server doesn't know that key, then SSH tries the next one. You can enumerate all of someone's keys this way (like this SSH server does)
If you want to disable this sort of behaviour you can disable SSH from sending keys automatically, and then tell SSH which identity files need to be sent to each host.
In your .ssh/config, something like:
# Ignore SSH keys unless specified in Host subsection
IdentitiesOnly yes
# Send your public key to github only
Host github.com
IdentityFile ~/.ssh/id_rsa
This is also handy if you're security conscious and like to use a different private/public key pair for each host you have an account with!
If you want to disable this sort of behaviour you can disable SSH from sending keys automatically, and then tell SSH which identity files need to be sent to each host.
In your .ssh/config, something like:
This is also handy if you're security conscious and like to use a different private/public key pair for each host you have an account with!