Users Guide

the no version of this command to reactivate the Telnet or SSH session capability for the device. Use the
show restrict-access command to view whether the access to a device using Telnet or SSH is disabled or
not.
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
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
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Security