Allied Telesis AT-S63 User Manual

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Chapter 31: 802.1x Port-based Network Access Control
370
Section VIII: Port Security
Supplicant and VLAN Associations
One of the challenges to managing a network is accommodating end 
users that roam. These are individuals whose work requires that they 
access the network resources from different points at different times. The 
difficulty arises in providing them with access to the same network 
resources and, conversely, restricting them from unauthorized areas, 
regardless of the workstation from where they access the network. A 
closely related issue is where a workstation is employed at various times 
by different individuals with unique requirements in terms of network 
resources and security levels.
Providing network users with access to their network resources while also 
maintaining network security is often achieved through the use of VLANs. 
As explained in “Overview” on page 249, a VLAN is an independent traffic 
domain where the traffic generated by the nodes within the VLAN is 
restricted to nodes of the same VLAN, unless there is a router or Layer 3 
device. Different users are assigned to different VLANs depending on their 
resource requirements and security level.
The problem with a port-based VLAN is that VLAN membership is 
determined by the port on the switch to which the device is connected. If a 
different device that needs to belong to a different VLAN is connected to 
the port, the port must be manually moved to the new VLAN using the 
management software.
With 802.1x port-based network access control, you can link a username 
and password combination or MAC address to a specific VLAN so that the 
switch automatically moves the port to the appropriate VLAN when a client 
logs on. This frees the network manager from having to reconfigure 
VLANs as end users access the network from different points or where the 
same workstation is used by different individuals at different times.
To use this feature, you have to enter a VLAN identifier, along with other 
information, when you create a supplicant account on the RADIUS server. 
The server passes the identifier to the switch when a user logs on with a 
valid username and password combination or MAC address, depending 
on the authentication method. The information to provide on the RADIUS 
server is outlined in “Supplicant VLAN Attributes on the RADIUS Server” 
on page 371
.
How the switch responses when it receives VLAN information during the 
authentication process can differ depending on the operating mode of the 
authenticator port.