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9120ax Access Point not joining 3504 wlc

9120 AX Access point not joining controller ( code) and the error I am getting at every turn is - Waiting for preferred uplink IP configuration - anyone have anything I can try.  I did try to manually place IP on access point.  Under Security tab - AP Policies - I checked first 3 boxes for certs SSC MIC and LSC.  Also under Controller Tab - Advanced - DHCP - I enabled DHCP proxy - which was unchecked.  I have since taken those configs off as there was no change in AP.  Any idea on how to get this set?  

VIP Mentor

Did you try placing AP on the same vlan as WLC management vlan ?


If possible attach AP console output to have a look.





it is untagged.  Trying to use as test AP for ax/WiFi 6.  This is main output as it comes up.

*06/27/2019 00:06:47.4880] <=== Deactivate Deep Green Mode
[*06/27/2019 00:06:51.3090] Waiting for preferred uplink IP configuration
[*06/27/2019 00:06:56.3160] Waiting for preferred uplink IP configuration
[*06/27/2019 00:07:01.3230] Waiting for preferred uplink IP configuration
[*06/27/2019 00:07:02.3280] Resetting wired0 and restart DHCP client
[*06/27/2019 00:07:02.5190] wired0 (Ext switch port: 7) (Logical Port: 15) (phyId: 1f) Link DOWN.
[*06/27/2019 00:07:02.5190] ===> Activate Deep Green Mode
[*06/27/2019 00:07:04.5240] wired0 (Ext switch port: 7) (Logical Port: 15) (phyId: 1f) Link UP at 1000 mbps full


Your AP simply has no IP.

You could add a dhcp server on the vlan the ap's reside or you'll have to console in each ap and give them an ip manually. Capwap ap ip x.x.x.x 255.x.x.x x.x.x.x


First being ip then mask and then gateway. If the controller is on the same vlan then you wont need to point the aps towards the controller.



Configuring a static IP address on the AP via Console port worked for me:

capwap ap ip

After a reload of the AP, it happily joined its controller:



Hall of Fame Community Legend

@ThisisIT22 wrote:

Waiting for preferred uplink IP configuration

This error message means the AP is "waiting" (and waiting) for a response from the DHCP server. 

Is DHCP Option 43 configured correctly?


It looks like no dhcp at all never mind option 43 Leo :)
I'm with Joey - check dhcp server configuration or configure static IP.

AP Policies - I checked first 3 boxes for certs SSC MIC and LSC


I know you have lot of good information below, but I am just curious are you using your own CA signed certs or self signed cert on AP, if now why you have SSC and LSC checked ? If Yes then why do you have MIC checked ?

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Im having the same issue with my Catalyst 9115AX. 


We have the WLC Cat 9800-40 with the software version 16.12.


We have configure the AP with static IP.  The AP is able to have connectivity with the same network and others but in certain momment this log appear :  


[*10/28/2019 18:14:48.5730] wired0 (Ext switch port: 7) (Logical Port: 15) (phyId: 1e) Link DOWN.
[*10/28/2019 18:14:48.5730] ===> Activate Deep Green Mode

and then, it lose connectivity even with the Gateway.


This makes the Controller to Disjoin the AP.


Does anyone know what could happen?

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