285
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 is 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 on-going backend
Summary of Contents for NS4750-24S-4T-4X
Page 1: ...NS4750 24S 4T 4X User Manual P N 1702826 REV 00 01 ISS 14JUL14 ...
Page 56: ...56 Figure 4 2 7 Privilege Levels Configuration Page Screenshot ...
Page 110: ...110 Figure 4 4 6 Mirror Configuration Page Screenshot ...
Page 117: ...117 Figure 4 5 4 LACP Port Configuration Page Screenshot ...
Page 174: ...174 Figure 4 7 10 MST1 MSTI Port Configuration Page Screenshot ...
Page 180: ...180 Figure 4 8 2 Multicast Flooding ...
Page 249: ...249 Figure 4 9 18 Voice VLAN Configuration Page Screenshot ...
Page 271: ...271 Counter Counts the number of frames that match this ACE ...
Page 281: ...281 Figure 4 11 4 Network Access Server Configuration Page Screenshot ...
Page 315: ...315 ...
Page 328: ...328 ...
Page 335: ...335 ...
Page 346: ...346 Figure 4 14 1 LLDP Configuration Page Screenshot ...
Page 350: ...350 Figure 4 14 2 LLDP MED Configuration Page Screenshot ...
Page 372: ...372 Figure 4 16 1 Loop Protection Configuration Page Screenshot ...