Optical Systems Design OSD2512 User Manual page 93

MAC-based authentication allows for authentication of more than one user on the
same port, and doesn't require the user to have special 802.1X supplicant software
installed on his system. The switch uses the user's MAC address to authenticate
against the backend server. Intruders can create counterfeit MAC addresses, which
makes MAC-based authentication less secure than 802.1X authentication.
The NAS configuration consists of two sections, a system- and a port-wide.
SYSTEM CONFIGURATION
Mode
Indicates if NAS is globally enabled or disabled on the switch. If globally disabled, all ports
are allowed forwarding of frames.
Reauthentication Enabled
If checked, successfully authenticated supplicants/clients are reauthenticated after the interval
specified by the Reauthentication Period. Reauthentication for 802.1X-enabled ports can be
used to detect if a new device is plugged into a switch port or if a supplicant is no longer
attached.
For MAC-based ports, reauthentication is only useful if the RADIUS server configuration has
changed. It does not involve communication between the switch and the client, and therefore
doesn't imply that a client is still present on a port (see Aging Period below).
Reauthentication Period
Determines the period, in seconds, after which a connected client must be reauthenticated.
This is only active if the Reauthentication Enabled checkbox is checked. Valid values are in
the range 1 to 3600 seconds.
EAPOL Timeout
Determines the time for retransmission of Request Identity EAPOL frames.
Valid values are in the range 1 to 65535 seconds. This has no effect for MAC-based ports.
Aging Period
This setting applies to the following modes, i.e. modes using the Port Security functionality to
secure MAC addresses:
• Single 802.1X
• Multi 802.1X
• MAC-Based Auth.
When the NAS module uses the Port Security module to secure MAC addresses, the Port
Security module needs to check for activity on the MAC address in question at regular
intervals and free resources if no activity is seen within a given period of time. This parameter
controls exactly this period and can be set to a number between 10 and 1000000 seconds.
If reauthentication is enabled and the port is in an 802.1X-based mode, this is not so critical,
since supplicants that are no longer attached to the port will get removed upon the next
reauthentication, which will fail. But if reauthentication is not enabled, the only way to free
resources is by aging the entries.
For ports in MAC-based Auth. mode, reauthentication doesn't cause direct communication
between the switch and the client, so this will not detect whether the client is still attached or
not, and the only way to free any resources is to age the entry.
PAGE 93
OPTICAL SYSTEMS DESIGN
OSD2512 OPERATOR MANUAL
DOC ID: 10118101