The authentication-mode none command configures none as the authentication mode for VTY user logins.
By default, no authentication mode is configured for VTY user logins. User can log in only after an authentication mode is configured.
This command is available to aid upgrade compatibility. It can only be run during the configuration restoration phase of the upgrade.
To configure none as the authentication mode for VTY user logins, run the authentication-mode none command. After this command is configured, VTY users can log in without authentication, posing a security risk. To eliminate this risk, run the undo authentication-mode command to delete this configuration or run the authentication-mode aaa command in the VTY view to switch the authentication mode to AAA.