Authenticating Remote Server Hosts
Remote Secure Shell servers are authenticated by a public-key procedure.
The user checks the fingerprint of the remote server's public key. When
the user has approved the public key, it is stored in the user's
$HOME/.ssh2/hostkeys directory and will be used automatically thereafter.
The verification step normally requires user interaction, so even for
users that are set up to run client programs unattended, 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.
ssh-keydist-g3 is run with the
option, it accepts the received host keys automatically without prompting
the user. You should verify the validity of keys after receiving them or you
risk being subject to a man-in-the-middle attack.
When the host key is received during the first connection to a remote host
(or when the host key has changed) and you choose to save the key, its
filename is by default stored in hashed format,
hhh is a hash of the host port and name. The saved file contains a
hash of the host's public key. The hashed host key format is a security
feature to make address harvesting on the hosts difficult.
In the plain (traditional) format, the name of a host key file includes
the hosts's name and port, as in
and the file contains the host's public key in plaintext format.
The key storage format can be set in the
configuration file, or on the
ssh-keydist-g3 command line with the
-F option. The command-line option takes precedence over the setting
in the configuration file.