Ports In Authorized And Unauthorized States - Cisco Catalyst 2960-XR Security Configuration Manual

Configuring IEEE 802.1x Port-Based Authentication

Ports in Authorized and Unauthorized States

During 802.1x authentication, depending on the switch port state, the switch can grant a client access to the
network. The port starts in the unauthorized state. While in this state, the port that is not configured as a voice
VLAN port disallows all ingress and egress traffic except for 802.1x authentication, CDP, and STP packets.
When a client is successfully authenticated, the port changes to the authorized state, allowing all traffic for
the client to flow normally. If the port is configured as a voice VLAN port, the port allows VoIP traffic and
802.1x protocol packets before the client is successfully authenticated.
If a client that does not support 802.1x authentication connects to an unauthorized 802.1x port, the switch
requests the client's identity. In this situation, the client does not respond to the request, the port remains in
the unauthorized state, and the client is not granted access to the network.
In contrast, when an 802.1x-enabled client connects to a port that is not running the 802.1x standard, the client
initiates the authentication process by sending the EAPOL-start frame. When no response is received, the
client sends the request for a fixed number of times. Because no response is received, the client begins sending
frames as if the port is in the authorized state.
You control the port authorization state by using the authentication port-control interface configuration
command and these keywords:
• force-authorized—disables 802.1x authentication and causes the port to change to the authorized state
• force-unauthorized—causes the port to remain in the unauthorized state, ignoring all attempts by the
• auto—enables 802.1x authentication and causes the port to begin in the unauthorized state, allowing
In Session Aware Networking mode, the authentication port-control command is access-session
Note
port-control.
If the client is successfully authenticated (receives an Accept frame from the authentication server), the port
state changes to authorized, and all frames from the authenticated client are allowed through the port. If the
authentication fails, the port remains in the unauthorized state, but authentication can be retried. If the
authentication server cannot be reached, the switch can resend the request. If no response is received from
the server after the specified number of attempts, authentication fails, and network access is not granted.
When a client logs off, it sends an EAPOL-logoff message, causing the switch port to change to the unauthorized
state.
If the link state of a port changes from up to down, or if an EAPOL-logoff frame is received, the port returns
to the unauthorized state.
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without any authentication exchange required. The port sends and receives normal traffic without
802.1x-based authentication of the client. This is the default setting.
client to authenticate. The switch cannot provide authentication services to the client through the port.
only EAPOL frames to be sent and received through the port. The authentication process begins when
the link state of the port changes from down to up or when an EAPOL-start frame is received. The switch
requests the identity of the client and begins relaying authentication messages between the client and
the authentication server. Each client attempting to access the network is uniquely identified by the
switch by using the client MAC address.
Catalyst 2960-XR Switch Security Configuration Guide, Cisco IOS Release 15.0(2)EX1
Ports in Authorized and Unauthorized States
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