Information About Passive Clients
Passive Clients are wireless devices, such as printers and devices configured using a static IP address. Such clients do no transmit any IP information after associating to an AP. That is why, the controller does not learn their IP address unless they perform the DHCP process.
In the controller, the clients just show up in the Learn IP state and get timed out because of the DHCP policy-timeout.
Non-Cisco WGB devices are wireless devices that do not perform L2 or L3 address registration for the wired clients behind them.
The Passive Client feature can be enabled on a per WLAN basis. Enabling this feature will change a few default behaviors in order to better accommodate passive clients and non-Cisco WGB devices. These changes include :
No client will ever timeout in the IP_LEARN phase. The controller will keep on waiting to learn their IP address. Note that the idle timeout remains active and will delete the client entry after the timeout period expiry, if the client remains silent all along.
ARP coming from the wired side is broadcasted to all the APs, if the controller does not know the client IP address, to ensure that it reaches the passive client. After this, the controller learns the client IP from the ARP response.
Device tracking (DHCP Relay support, ARP proxy, and so on) is disabled for the client.
Passive client devices are in IP LEARN state on the controller once connected and they remain in the same state until some other devices try to reach out to it. If a device tries to connect a passive client device by performing an address resolution protocol (ARP) or through other means, you can learn the passive client IP address and move the same to RUN state on the controller. While the client waits in IP LEARN state, the time out for that client is disabled. The no ip-mac-binding configuration is mandatory if there is an overlapping IP within the FlexConnect Site. Otherwise, this configuration is optional.
The following combinations are supported when passive-client is configured with non-Cisco WGB devices:
Local mode + central switching + central DHCP
No DHCP relay and server related configurations must be available in the policy profile and client VLAN interface configurations. This is applicable for both Passive clients and non-Cisco WGB devices.