The ssh client first-time enable command enables the first authentication on the SSH client.
The undo ssh client first-time enable command disables the first authentication on the SSH client.
By default, the first authentication is disabled on the SSH client.
Usage Scenario
When the SSH client accesses the SSH server for the first time and the public key of the SSH server is not configured on the SSH client, you can enable the first authentication for the SSH client to access the SSH server and save the public key on the SSH client. When the SSH client accesses the SSH server next time, the saved public key is used to authenticate the SSH server.