Brocade TurboIron 24X Series Configuration Guide - Manual (Page 979)

Brocade TurboIron 24X Series Configuration Guide 945
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How 802.1X port security works
Message exchange during authentication
Figure 117 illustrates a sample exchange of messages between an 802.1X-enabled Client, a switch
acting as Authenticator, and a RADIUS server acting as an Authentication Server.
FIGURE 117 Message exchange between client/supplicant, authenticator, and authentication
server
In this example, the Authenticator initiates communication with an 802.1X-enabled Client. When
the Client responds, it is prompted for a username (48 characters maximum) and password. The
Authenticator passes this information to the Authentication Server, which determines whether the
Client can access services provided by the Authenticator. When the Client is successfully
authenticated by the RADIUS server, the port is authorized. When the Client logs off, the port
becomes unauthorized again.
The Brocade 802.1X implementation supports dynamic VLAN assignment. If one of the attributes
in the Access-Accept message sent by the RADIUS server specifies a VLAN identifier, and this VLAN
is available on the device, the client port is moved from its default VLAN to the specified VLAN.
When the client disconnects from the network, the port is placed back in its default VLAN.Refer to
“Configuring dynamic VLAN assignment for 802.1X ports” on page 954 for more information.
If a Client does not support 802.1X, authentication cannot take place. The device sends
EAP-Request/Identity frames to the Client, but the Client does not respond to them.
When a Client that supports 802.1X attempts to gain access through a non-802.1X-enabled port, it
sends an EAP start frame to the device. When the device does not respond, the Client considers
the port to be authorized, and starts sending normal traffic.
Devices support Identity and MD5-challenge requests in EAP Request/Response messages.
NOTE
Refer to also “EAP pass-through support” on page 946.
RADIUS Server
(Authentication Server) Client/Supplicant
Port Unauthorized
EAP-Response/Identity
EAP-Request/Identity
EAP-Response/Identity
EAP-Request/MD5-Challenge
EAP-Success
EAP-Logoff
Port Authorized
Port Unauthorized
RADIUS Access-Request
RADIUS Access-Challenge
RADIUS Access-Request
RADIUS Access-Accept
Switch
(Authenticator)