Remote Secure Shell servers are authenticated using either traditional public-key authentication or certificate authentication.
In traditional public-key authentication, the user verifies the
fingerprint of the remote server's public key. When the user has approved
the public key, it is stored in the user's
directory and will be used automatically thereafter.
The verification step requires user interaction, so even for users that are set up to run client programs unattended (Under MVS), the first connection must be done by a person who logs in as the user, accesses the remote server, and goes through the fingerprint check dialog. The same steps must be repeated if the remote host's key is changed.
Optionally, the ssh-keyfetch tool can be used for storing the remote server keys before the connections are made. See ssh-keyfetch(1).
For more information on server authentication using public keys, see Server Authentication with Public Keys in File.