I am trying to SSH into my fresh Ubuntu 12.04 server. At the client I have deleted known_hosts. SSH to the host for the first time has it offering me an ECDSA key to verify. The problem is I know how to get the RSA key and verify it but I don't know how to get the ECDSA key.
How can I force SSH to prompt with the RSA key and store it if I approve?
I have tried:
ssh -o RSAAuthentication=yes user@server
Unfortunately this gives me an ECDSA key and the Are you sure you want to continue connecting (yes/no)?
message.
RSAAuthentication
(and the relatedRhostsRSAAuthentication
also) was about authenticating the client, not the host, and only in SSHv1, which was broken and obsolete last century. OpenSSH 7.5 in 2017 (well after this Q was asked) removed SSHv1 entirely and disabled related options. The option for PKC client auth in SSHv2 isPubkeyAuthentication
. The server always uses PKC auth, so there is no option to enable it, only to tailor it withHostKeyAlgorithms
as correctly answered.