Allworx PowerFlex P810, Руководство пользователя

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PowerFlex
8/24/48 Port GbE PoE Managed Switch User’s Guide
upon the next backend authentication server request from the switch. This
scenario loops forever. Therefore, the server timeout should be smaller than
the supplicant’s EAPOL Start frame retransmission rate.
Single 802.1X In port-based 802.1X authentication, once a supplicant is successfully
authenticated on a port, the whole port is opened for network traffic. This
allows other clients connected to the port (for instance through a hub) to piggy-
back on the successfully authenticated client and get network access even
though each is really are not authenticated. To overcome this security breach,
use the Single 802.1X variant.Single 802.1X is not an IEEE standard, but
features many of the same characteristics as port-based 802.1X. In Single
802.1X, at most one supplicant can get authenticated on the port at a time.
Normal EAPOL frames are used in the communication between the supplicant
and the switch. If more than one supplicant is connected to a port, the one that
comes first when the port's link comes up will be the first one considered. If that
supplicant does not provide valid credentials within a certain amount of time,
another supplicant will get a chance. Once a supplicant is successfully
authenticated, only that supplicant has access. This is the most secure of all
the supported modes. In this mode, the Port Security module is used to secure
a supplicant's MAC address once successfully authenticated.
Multi 802.1X In port-based 802.1X authentication, once a supplicant is successfully
authenticated on a port, the whole port is opened for network traffic. This
enables other clients connected to the port (for instance through a hub) to
piggy-back on the successfully authenticated client and get network access
even though each is really are not authenticated. To overcome this security
breach, use the Multi 802.1X variant.
Multi 802.1X is not an IEEE standard, but features many of the same
characteristics as port-based 802.1X. Multi 802.1X is like Single 802.1X - not
an IEEE standard, but a variant that features many of the same characteristics.
In Multi 802.1X, one or more supplicants can get authenticated on the same
port at the same time. Each supplicant is authenticated individually and
secured in the MAC table using the Port Security module.
In Multi 802.1X it is not possible to use the multicast BPDU MAC address as
destination MAC address for EAPOL frames sent from the switch towards the
supplicant, since that would cause all supplicants attached to the port to reply
to requests sent from the switch. Instead, the switch uses the supplicant's MAC
address, which is obtained from the first EAPOL Start or EAPOL Response
Identity frame sent by the supplicant. An exception to this is when no
supplicants are attached. In this case, the switch sends EAPOL Request
Identity frames using the BPDU multicast MAC address as destination - to
wake up any supplicants that might be on the port.
The maximum number of supplicants that can be attached to a port can be
limited using the Port Security Limit Control functionality.
MAC-based Auth. Unlike port-based 802.1X, MAC-based authentication is not a standard, but
merely a best-practices method adopted by the industry. In MAC-based
authentication, users are called clients, and the switch acts as the supplicant
on behalf of clients. The initial frame (any kind of frame) sent by a client is
snooped by the switch, which in turn uses the client's MAC address as both
username and password in the subsequent EAP exchange with the RADIUS
server. The 6-byte MAC address is converted to a string of the following form
"xx-xx-xx-xx-xx-xx", that is, a dash (-) is used as separator between the lower-
case hexadecimal digits. The switch only supports the MD5 -Challenge
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Revised: October 30, 2013
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