With the 7.0 release, OpenSSH disabled ssh-dss keys. The not-so-recommended workaround is to explicitly re-add DSA key support to .ssh/config, which will eventually be dropped by a later OpenSSH version:PubkeyAcceptedKeyTypes=+ssh-dssAs I have deployed my DSA key to countless machines (and I do not have a full list of them, as known_hosts is hashed), I have to replace the old public user key whenever I encounter it on login.Is it possible to make the OpenSSH client display a warning when I log in with an ssh-dss key?
SSH: display warning when using (deprecated) ssh-dss key
ssh;authentication;openssh
There is no special mechanism in ssh to notify you that you use some key. It works or fails.Differentiate the keys using passphraseOnly other idea that comes to my mind is differentiate between the keys using passphrase.For example, have the RSA keys in ssh-agent or without passphrase and the DSA one with passphrase (and not in ssh-agent). It might warn you with passphrase prompt.Not to use themThe easiest thing is not to add the above line into ssh_config and then you will see when you can't connect. Then you can use the options on command line for individual connections:ssh -oPubkeyAcceptedKeyTypes=+ssh-dss host