Cisco Catalyst 3750-E Series, Руководство по настройке программного обеспечения

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Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-08
Chapter 10 Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
In single-host mode, only the IP phone is allowed on the voice VLAN. In multiple-hosts mode,
additional clients can send traffic on the voice VLAN after a supplicant is authenticated on the PVID.
When multiple-hosts mode is enabled, the supplicant authentication affects both the PVID and the
VVID.
Note
If an IP phone and PC are connected to a switchport, and the port is configured in single- or multi-host
mode, we do not recommend configuring that port in standalone MAC authentication bypass mode. We
recommend only using MAC authentication bypass as a fallback method to 802.1x authentication with
the timeout period set to the default of five seconds.
A voice VLAN port becomes active when there is a link, and the device MAC address appears after the
first CDP message from the IP phone. Cisco IP phones do not relay CDP messages from other devices.
As a result, if several IP phones are connected in series, the switch recognizes only the one directly
connected to it. When IEEE 802.1x authentication is enabled on a voice VLAN port, the switch drops
packets from unrecognized IP phones more than one hop away.
When IEEE 802.1x authentication is enabled on a port, you cannot configure a port VLAN that is equal
to a voice VLAN.
Note
If you enable IEEE 802.1x authentication on an access port on which a voice VLAN is configured and
to which a Cisco IP Phone is connected, the Cisco IP phone loses connectivity to the switch for up to 30
seconds.
For more information about voice VLANs, see Chapter 15, “Configuring Voice VLAN.”
IEEE 802.1x Authentication with Port Security
You can configure an IEEE 802.1x port with port security in either single-host or multiple-hosts mode.
(You also must configure port security on the port by using the
switchport port-security interface
configuration command.) When you enable port security and IEEE 802.1x authentication on a port, IEEE
802.1x authentication authenticates the port, and port security manages network access for all MAC
addresses, including that of the client. You can then limit the number or group of clients that can access
the network through an IEEE 802.1x port.
These are some examples of the interaction between IEEE 802.1x authentication and port security on the
switch:
•
When a client is authenticated, and the port security table is not full, the client MAC address is added
to the port security list of secure hosts. The port then proceeds to come up normally.
When a client is authenticated and manually configured for port security, it is guaranteed an entry
in the secure host table (unless port security static aging has been enabled).
A security violation occurs if the client is authenticated, but the port security table is full. This can
happen if the maximum number of secure hosts has been statically configured or if the client ages
out of the secure host table. If the client address is aged, its place in the secure host table can be
taken by another host.
If the security violation is caused by the first authenticated host, the port becomes error-disabled and
immediately shuts down.
The port security violation modes determine the action for security violations. For more
information, see the
“Security Violations” section on page 26-10 .