Concept Guide

CONFIGURATION mode
aaa radius auth-method mschapv2
3 Establish a host address and password.
CONFIGURATION mode
radius-server host H key K
4 Log in to switch using console or telnet or ssh with a valid user role.
When 1-factor authentication is used, the authentication succeeds enabling you to access the switch. When two-factor authentication is
used, the system prompts you to enter a one-time password as a second step of authentication. If a valid one-time password is supplied,
the authentication succeeds enabling you to access the switch.
Support for Change of Authorization and Disconnect
Messages packets
The Network Access Server (NAS) uses RADIUS to authenticate AAA or dot1x user-access to the switch. The RADIUS service does not
support unsolicited messages sent from the RADIUS server to the NAS.
However, there are many instances in which it is desirable for changes to be made to session characteristics, without requiring the NAS to
initiate the exchange. For example, it may be desirable for administrators to be able to terminate user sessions in progress.
Alternatively, if the user changes authorization level, this change may require that authorization attributes be added or deleted from the
user sessions.
To overcome these limitations, Dell EMC Networking OS provides RADIUS extension commands in order to enable unsolicited messages to
be sent to the NAS. These extension commands provide support for Disconnect Messages (DMs) and Change-of-Authorization (CoA)
packets. DMs cause user sessions to be terminated immediately; whereas, CoA packets modify session authorization attributes such as
VLAN IDs, user privileges, and so on.
Change of Authorization (CoA) packets
Using the CoA packets, the NAS can handle authorization of dot1x sessions by processing the following requests from the Dynamic
Authorization Client (DAC): Re-authentication of the supplicant, Port disable, and Port bounce.
The CoA packets constitute one message request (CoA request) and one of the following two possible responses:
• Change of Authorization Acknowledgement (CoA-Ack) - If the authorization state change is successful, then NAS sends a CoA-Ack.
• Change of Authorization non-Acknowledgement (CoA-Nak) - If the authorization state change is not successful, then the NAS sends a
CoA-Nak, which is a negative acknowledgement.
Disconnect Messages
Using the Disconnect Messages, the NAS can disconnect AAA and dot1x sessions. NAS can disconnect AAA sessions using either
username or a combination of the username and session id. NAS can disconnect dot1x sessions using NAS-port, or calling-station ID, or
both.
The disconnect messages constitue one message request (DM request) and one of the following two possible responses:
• Disconnect Acknowledgement (DM-Ack) - If the session is disconnected successfully, then NAS sends a DM-Ack.
• Disconnect non-Acknowledgement (DM-Nak) - If the session is not disconnected successfully, then NAS sends a DM-Nak.
Security
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