The server is run as a started task under the SSHD2 user as described in Section Running as a Started Task, one server on each LPAR that will be accessed.
Each system (LPAR) has its own /etc/ssh2 directory. A server key is generated for each system. The Mainframe Security Group publishes the fingerprints of these keys.
The remote users download the server public key on the first Secure Shell access to the mainframe and whenever the server key has been changed. This access must be interactive and the user must verify the key by its fingerprint and allow the Secure Shell client program to write it to the user's $HOME/.sshx directory. The directory is $HOME/.ssh2/hostkeys for SSH Tectia Client on Unix and $HOME/.ssh/known_hosts for OpenSSH clients. SSH Tectia Client on Windows stores the key in the "%USERPROFILE%\Application Data\SSH\HostKeys" directory.
To set up client access, the users must access all the mainframe systems. When this is done, accessing the mainframe only requires the users to enter their passwords.