Authentication Process - D-Link DES-3528 - xStack Switch - Stackable Reference Manual

xStack® DES-3528/DES-3552 Series Layer 2 Stackable Fast Ethernet Managed Switch Web UI Reference Guide

Authentication Process

Utilizing the three roles stated above, the 802.1X protocol
provides a stable and secure way of authorizing and
authenticating users attempting to access the network.
Only EAPOL traffic is allowed to pass through the
specified port before a successful authentication is made.
This port is "locked" until the point when a Client with the
correct username and password (and MAC address if
802.1X is enabled by MAC address) is granted access
and therefore successfully "unlocks" the port. Once
unlocked, normal traffic is allowed to pass through the
port. The following figure displays a more detailed
explanation of how the authentication process is
completed between the three roles stated above.
The D-Link implementation of 802.1X allows network administrators to choose between two types of Access Control
used on the Switch, which are:
1. Port-Based Access Control – This method requires only one user to be authenticated per port by a remote
RADIUS server to allow the remaining users on the same port access to the network.
2. Host-Based Access Control – Using this method, the Switch will automatically learn up to a maximum of 448
MAC addresses by port and set them in a list. Each MAC address must be authenticated by the Switch using a
remote RADIUS server before being allowed access to the Network.
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 Bridge
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
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.
Figure 8-6 The 802.1X Authentication Process
Ethernet Switch
802.1X 802.1X 802.1X
802.1X
Client Client Client
Client
Network access controlled port
Network access uncontrolled port
Figure 8-7 Example of Typical Port-based Configuration
204
RADIUS
Server
...
802.1X 802.1X 802.1X 802.1X
802.1X
Client Client Client Client
Client