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[Archive] [WLC] Troubleshooting device-fingerprinting and configuration tips



Article ID: KB27714 KB Last Updated: 10 Oct 2020Version: 2.0

This article describes the traces that must be enabled in order to troubleshoot any issues with the device-fingerprinting feature. It also lists a few key points to remember about this feature.


To troubleshoot device-fingerprinting-related issues, configure the following traces:

#set trace sm level 8
#set ap x trace station filter devdetect_err
#set ap x trace station filter devdetect_debug_1
#set ap x trace station filter devdetect_debug_2
  • The feature kicks in only after the client is in the AUTHORIZED state. This means it already has an IP address. This means it will NOT be possible to change the VLAN unless a different system can force the client to re-DHCP. The clients will be fingerprinted after they get the IP address from the initial VLAN. It is possible to configure a different VLAN to be set after the clients are fingerprinted, but the client will have an incorrect IP address in the new VLAN until a DHCP renew is issued. The WLAN cannot force the client to renew.

  • The fingerprints are inspected in the configured order until a match is found.

  • If a more specific fingerprint is configured that must be matched,first delete the default fingerprint that can also be matched. This must be done because the first time a custom fingerprint is defined, the default fingerprint will have priority over the custom fingerprint based on configured order.

  • The default fingerprints can be restored with the command: # restore default-fingerprints. Now the custom fingerprint will have priority over the default ones.

  • If more custom fingerprints are defined after restoring the default fingerprints, be sure to delete the latter in order to give priority to the former.
Modification History:
2020-10-10: Archived article.
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