Windows DHCP option 43 not working

[tachyon05]

Access Point keeps registering to the wrong WLC, ignoring the WLC I specified in option 43.  I confirmed the HEX value is correctly entered on the DHCP server using multiple generators.  Any suggestions?

[tachyon05]

Thanks.  I will connect the AP to console cable, reach out to TAC, and share a resolution when I have it.  Thanks everyone.

[MHM Cisco World]

Ok' since you want to do that.

I am 50% sure the dhcp is push wlc IP to ap. 

But to be sure.

PowerOff the AP for 5 min powerOn and check wlc IP in AP.

[tachyon05]

Leaving the AP off and then power on didn't help.

Here are relevant console output, and you are correct that AP got the correct WLC IP initially but eventually joined the old WLC.

[*07/25/2023 23:41:53.3178] Got WLC address [correct WLC IP] from DHCP.
[*07/25/2023 23:41:53.3179] IP DNS query for CISCO-CAPWAP-CONTROLLER.[aaa.bbb.ccc]
[*07/25/2023 23:41:53.3224] DNS resolved CISCO-CAPWAP-CONTROLLER.[aaa.bbb.ccc]
[*07/25/2023 23:41:53.3225] DNS discover IP addr: [wrong WLC IP]
[*07/25/2023 23:41:53.3253] Discovery Request sent to [wrong WLC IP], discovery type STATIC_CONFIG(1)
[*07/25/2023 23:41:53.3280] Discovery Request sent to [correct WLC IP], discovery type DHCP(2)
[*07/25/2023 23:41:53.3342] Discovery Request sent to 255.255.255.255, discovery type UNKNOWN(0)
[*07/25/2023 23:41:53.3347]
[*07/25/2023 23:41:53.3347] CAPWAP State: Discovery
[*07/25/2023 23:41:53.3358] Discovery Response from [wrong WLC IP]
[*07/25/2023 23:41:57.9684] Start: RPC thread 2714305424 created.
[*07/27/2023 16:45:32.0004]
[*07/27/2023 16:45:32.0004] CAPWAP State: DTLS Setup
[*07/27/2023 16:45:32.3918]
[*07/27/2023 16:45:32.3918] CAPWAP State: Join
[*07/27/2023 16:45:32.3979] Sending Join request to [wrong WLC IP]

[tachyon05]

Thanks Everyone.  What got the AP to register to the correct WLC was to temporarily disable the DNS entry for CISCO-CAPWAP-CONTROLLER first, and then factory reset the AP.

[Rich R]

And had you tried factory reset before that?

[tachyon05]

Yes.  However, factory reset without the temporarily removing DNS entry didn't resolve the issue for some reason.

[Rich R]

Is the DNS entry serving information that conflicts/differs with/from option 43, local subnet discovery or helper address?
How did the AP discover the WLC without DNS?
It sounds like you're using multiple and conflicting sources of WLC discovery.