Understanding 802.1X Port-Based And Host-Based Network Access Control - D-Link xStack DGS-3200-10 User Manual

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xStack DGS-3200 Series Layer 2 Gigabit Ethernet Managed Switch

Understanding 802.1X Port-based and Host-based Network Access Control

The original intent behind the development of 802.1X was to leverage the characteristics of point-to-point in LANs. As any single
LAN segment in such infrastructures has no more than two devices attached to it, one of which is a Brid ge Port. The Bridge Port
detects events that indicate the attachment of an active device at the remote end of the link, or an active device becoming inactive.
These events can be used to control the authorization state of the Port and initiate the process of authenticating the attached device
if the Port is unauthorized. This is the Port-Based Network Access Control.
Port-based Network Access Control
RADIUS
Server
Ethernet Switch
...
802.1X 802.1X 802.1X 802.1X 802.1X 802.1X 802.1X
802.1X 802.1X
Client Client Client Client Client Client Client
Client Client
Network access controlled port
Network access uncontrolled port
Figure 5 - 23. Example of Typical Port-based Configuration
Once the c onnected device has successfully been authenticated, the Po rt then becomes Authorized, and all sub sequent traffic on
the Port is not subject to access control restriction until an event occurs that causes the Port to become Unauthorized. Hence, if the
Port is actually connected to a shared media LAN segment with more than one attached device, successfully authenticating one of
the attached devices effectively provides access to the LAN for all devices on the shared segment. Clearly, the security offere d in
this situation is open to attack.
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