D-Link DES-1228/ME User Manual page 173

DES-1228/ME Layer 2 Fast Ethernet Managed Switch
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.
802.1X Port-based Access Control
Figure 10-18. Example of Typical Port-Based Configuration
Once the connected device has successfully been authenticated, the Port then becomes Authorized, and all subsequent 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 offered in
this situation is open to attack.
160