Session Termination
There are three types of CoA requests that can trigger session termination. A CoA Disconnect-Request
terminates the session, without disabling the host port. This command causes re-initialization of the authenticator
state machine for the specified host, but does not restrict that host access to the network.
To restrict a host
’
s access to the network, use a CoA Request with the
Cisco:Avpair="subscriber:command=disable-host-port" VSA. This command is useful when a host is known
to be causing problems on the network, and you need to immediately block network access for the host. When
you want to restore network access on the port, re-enable it using a non-RADIUS mechanism.
When a device with no supplicant, such as a printer, needs to acquire a new IP address (for example, after a
VLAN change), terminate the session on the host port with port-bounce (temporarily disable and then re-enable
the port).
CoA Disconnect-Request
This command is a standard Disconnect-Request. If the session cannot be located, the switch returns a
Disconnect-NAK message with the
“
Session Context Not Found
”
error-code attribute. If the session is located,
the switch terminates the session. After the session has been completely removed, the switch returns a
Disconnect-ACK.
If the switch fails-over to a standby switch before returning a Disconnect-ACK to the client, the process is
repeated on the new active switch when the request is re-sent from the client. If the session is not found
following re-sending, a Disconnect-ACK is sent with the
“
Session Context Not Found
”
error-code attribute.
Related Topics
Session Identification, on page 64
CoA Request: Disable Host Port
The RADIUS server CoA disable port command administratively shuts down the authentication port that is
hosting a session, resulting in session termination. This command is useful when a host is known to cause
problems on the network and network access needs to be immediately blocked for the host. To restore network
access on the port, reenable it using a non-RADIUS mechanism. This command is carried in a standard
CoA-Request message that has this new vendor-specific attribute (VSA):
Cisco:Avpair="subscriber:command=disable-host-port"
Because this command is session-oriented, it must be accompanied by one or more of the session identification
attributes described in the
“
Session Identification
”
section. If the session cannot be located, the switch returns
a CoA-NAK message with the
“
Session Context Not Found
”
error-code attribute. If the session is located, the
switch disables the hosting port and returns a CoA-ACK message.
If the switch fails before returning a CoA-ACK to the client, the process is repeated on the new active switch
when the request is re-sent from the client. If the switch fails after returning a CoA-ACK message to the client
but before the operation has completed, the operation is restarted on the new active switch.
Catalyst 2960-X Switch Security Configuration Guide, Cisco IOS Release 15.0(2)EX
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Configuring RADIUS
RADIUS Change of Authorization