Use GlobalKnownHostsFile instead of GlobalKnownHostsFile2 in ssh_config, as the latter has been deprecated in OpenSSH 5.9. If DNS host key verification is enabled, restrict the set of allowed host public key algorithms to ssh-rsa and ssh-dss, as DNS SSHFP records support only these algorithms. Make sure public key user authentication is enabled in both ssh and sshd. ticket 2769