Administrator Guide

AAA Authentication
Dell Networking OS supports a distributed client/server system implemented through authentication,
authorization, and accounting (AAA) to help secure networks against unauthorized access.
In the Dell Networking implementation, the Dell Networking system acts as a RADIUS or TACACS+ client and
sends authentication requests to a central remote authentication dial-in service (RADIUS) or Terminal access
controller access control system plus (TACACS+) server that contains all user authentication and network
service access information.
Dell Networking uses local usernames/passwords (stored on the Dell Networking system) or AAA for login
authentication. With AAA, you can specify the security protocol or mechanism for different login methods and
different users. In Dell Networking OS, AAA uses a list of authentication methods, called method lists, to
define the types of authentication and the sequence in which they are applied. You can define a method list
or use the default method list. User-defined method lists take precedence over the default method list.
NOTE: If a console user logs in with RADIUS authentication, the privilege level is applied from the RADIUS
server if the privilege level is configured for that user in RADIUS, whether you configure RADIUS
authorization.
Configuration Task List for AAA Authentication
The following sections provide the configuration tasks.
• Configure Login Authentication for Terminal Lines
• Configuring AAA Authentication Login Methods
• Enabling AAA Authentication
• Enabling AAA Authentication - RADIUS
For a complete list of all commands related to login authentication, refer to the Security chapter in the Dell
Networking OS Command Reference Guide.
Configure Login Authentication for Terminal Lines
You can assign up to five authentication methods to a method list. Dell Networking OS evaluates the methods
in the order in which you enter them in each list.
If the first method list does not respond or returns an error, Dell Networking OS applies the next method list
until the user either passes or fails the authentication. If the user fails a method list, Dell Networking OS does
not apply the next method list.
Configuring AAA Authentication Login Methods
To configure an authentication method and method list, use the following commands.
Dell Networking OS Behavior: If you use a method list on the console port in which RADIUS or TACACS is
the last authentication method, and the server is not reachable, Dell Networking OS allows access even
though the username and password credentials cannot be verified. Only the console port behaves this way,
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