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802.1X overview
802.1X is a port-based network access control protocol initially proposed for securing WLANs. The
protocol has also been widely used on Ethernet networks for access control.
802.1X controls network access by authenticating the devices connected to 802.1X-enabled LAN
ports.
802.1X architecture
802.1X operates in the client/server model. As shown in
, 802.1X authentication includes
the folllowing entities:
•
Client
(supplicant)
—A user terminal seeking access to the LAN. The terminal must have
802.1X software to authenticate to the access device.
•
Access device (authenticator)
—Authenticates the client to control access to the LAN. In a
typical 802.1X environment, the access device uses an authentication server to perform
authentication.
•
Authentication
server
—Provides authentication services for the access device. The
authentication server first authenticates 802.1X clients by using the data sent from the access
device. Then, the server returns the authentication results to the access device to make access
decisions. The authentication server is typically a RADIUS server. In a small LAN, you can use
the access device as the authentication server.
Figure 21 802.1X architecture
Controlled/uncontrolled port and port
authorization status
802.1X defines two logical ports for the network access port: controlled port and uncontrolled port.
Any packet arriving at the network access port is visible to both logical ports.
•
Uncontrolled
port
—Is always open to receive and transmit authentication packets.
•
Controlled
port
—Filters packets depending on the port's state.
{
Authorized state
—The controlled port is in authorized state when the client has passed
authentication. The port allows traffic to pass through.
{
Unauthorized state
—The port is in unauthorized state when the client has failed
authentication. The port controls traffic by using one of the following methods:
−
Performs bidirectional traffic control to deny traffic to and from the client.
−
Performs unidirectional traffic control to deny traffic from the client. The HPE devices
support only unidirectional traffic control.
