Cisco APIC Security Configuration Guide, Release 6.2(x)

802.1X authentication

Updated: April 17, 2026

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Describes how 802.1X uses an authentication server and EAPOL traffic to control client access through Cisco NX-OS device ports.

802.1X is a client-server access control and authentication protocol that prevents unauthorized clients from connecting to a LAN through switch ports.

The protocol provides these controls:

Each client must authenticate before it can access the network.
An authentication server verifies the identity of each client that connects to a Cisco NX-OS device port.
Until authentication succeeds, the port allows only Extensible Authentication Protocol over LAN (EAPOL) traffic from the client.

802.1X authentication components

802.1X authentication uses these components to control network access:

Table 1. 802.1X component roles
Component	Role
Client	Requests access through a Cisco NX-OS device port and exchanges EAPOL messages during authentication.
Cisco NX-OS device	Controls access to the port and forwards authentication and accounting requests to the authentication server as a RADIUS client.
RADIUS server	Provides centralized authentication and helps protect the network from unauthorized access.

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