# Authenticate administrators on engines using the Radius authentication method

You can authenticate administrators on an engine by using the RADIUS authentication method.

## Before you begin

- This feature is not supported for virtual engines.
- This feature is only supported on engine versions 7.1.3 and later.
- You must replicate administrator accounts on the engine to authenticate administrators on that engine using the RADIUS authentication method. For more details on replicating administrator accounts, refer to the Replicate administrator accounts topic.
- If a user disables the root account and downgrades the engine to a version that does not support radius authentication for engine, then the root account will remain unavailable even if the password is reset from SMC. Hence, it is recommended that the root account is enabled before downgrading the engine version.

##

## Steps

1. Configure the RADIUS authentication settings for the administrator. For more information, refer to the Authenticate administrators using RADIUS or TACACS+ methods topic.
2. Select Engine.
3. Right-click an engine, then select Edit <element type>.
4. Navigate to Advanced Settings > Authentication.
5. In the Root and Administrator Authentication section:
   1. From the Root Password Login drop-down list, select one of the following options:
      - Login Allowed via SSH and Console: The root password login to an engine is allowed via SSH and console.
        Note: By default, this option is selected if the engine is upgraded.
      - Login Allowed via Console Only: The root password login to an engine by using SSH is not allowed. But root password login by using console is allowed.
        Note: By default, this option is selected when we create a new engine.
      - Root Account Disabled (Super User Privileges through sudo): The root password login to an engine is disabled.
   2. From the Authentication Method drop-down list, select an authentication method element from the below options:
      - Local Password: Allows authentication using the local password.
      - [Select…]: Select this option to view the available radius authentication method elements.
        Note: The authentication method options are displayed as per the radius authentication server elements that are configured. For more details on how to create a radius authentication server element, refer to the Define Authentication Method elements for external servers topic.
   3. From the SSH Passwordless Login drop-down list, select one of the following options:
      - Allow: The SSH password less login is allowed.
      - Deny: The SSH password less login is denied.
      Note: This applies only to administrators replicated on the engine. For more details on administrator account replication, refer to the Add administrator accounts topic.
6. Click the Save and Refresh icon.