Intellinet 560931, Руководство пользователя

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Port Configuration
The table has a number of columns that allow you to configure the port mode based on the IEEE 802.1X
standard. Select the port and configure the settings.
Port
The port number for which the configuration below applies.
Admin State
If NAS is globally enabled, this selection controls the port's authentication mode. The following modes are
available:
Force Authorized
In this mode, the switch will send one EAPOL Success frame when the port link comes up, and any client
on the port will be allowed network access without authentication.
Force Unauthorized
In this mode, the switch will send one EAPOL Failure frame when the port link comes up, and any client
on the port will be disallowed network access.
Port
-­‐
based 802.1X
In the 802.1X world, the user is called the supplicant, the switch is the authenticator, and the RADIUS
server is the authentication server. The authenticator acts as the man in the middle, forwarding requests
and responses between the supplicant and the authentication server. Frames sent between the
supplicant and the switch are special 802.1X frames, known as EAPOL (EAP Over LANs) frames.
EAPOL frames encapsulate EAP PDUs (RFC3748). Frames sent between the switch and the RADIUS
server are RADIUS packets. RADIUS packets also encapsulate EAP PDUs together with other attributes
like the switch's IP address, name and the supplicant's port number on the switch. EAP is very flexible, in
that it allows for different authentication methods, like MD5-CHALLENGE, PEAP and TLS. The important
thing is that the authenticator (the switch) doesn't need to know which authentication method the
supplicant and the authentication server are using, or how many information exchange frames are
needed for a particular method. The switch simply encapsulates the EAP part of the frame into the
relevant type (EAPOL or RADIUS) and forwards it.
When authentication is complete, the RADIUS server sends a special packet containing a success or
failure indication. Besides forwarding this decision to the supplicant, the switch uses it to open up or block
traffic on the switch port connected to the supplicant.
Note: Suppose two backend servers are enabled and that the server timeout is configured to X seconds
(using the AAA configuration page), and suppose that the first server in the list is currently down (but not
considered dead). Now, if the supplicant retransmits EAPOL Start frames at a rate faster than X seconds,
then it will never get authenticated, because the switch will cancel ongoing backend authentication server
requests whenever it receives a new EAPOL Start frame from the supplicant. And since the server hasn't
yet failed (because the X seconds haven't expired), the same server will be contacted upon the next
backend authentication server request from the switch. This scenario will loop 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 they
really aren't authenticated. To overcome this security breach, use the Single 802.1X variant.
Single 802.1X is really not an IEEE standard, but features many of the same characteristics as does
port-based 802.1X. In Single 802.1X, at most one supplicant can get authenticated on the port at a time.