Controller don't discovery the APs

[Eng.AD27]

Hello Dear 

i have controller 9800-40 dont discover APs 9176 ? 

anyone here faced same problem  ? 

[Eng.AD27]

still same issue  
ip dhcp pool AA
network 172.18.250.0 255.255.255.0
option 43 hex f305.ac10.fac8.02
dns-server 172.18.250.200
lease infinite

[Leo Laohoo]

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@Eng.AD27 wrote:

option 43 hex f305.ac10.fac8.02

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This syntax is incorrect.

[Eng.AD27]

which one correct ? 

[Leo Laohoo]

Oh wait.  This is Fast Offline Migration.  

[Mark Elsen]

  - @Eng.AD27    Have a try by leaving the dots out in the 'option 43 hex....' directive.
                           the DHCP server might accept it, but the AP won't be able to parse it correctly —
                           leading to the "no WLC IP in DHCP option 43" error you're seeing.

                           Also add a domain-name , coming down too : 
                                          ip dhcp pool AA
                                          network 172.18.250.0 255.255.255.0
                                          option 43 hex f305ac10fac802
                                          dns-server 172.18.250.200
                                          domain-name example.local
                                          lease infinite

   M.

[Rich R]

> WLC assign the ips but the AP didn't receive IPs
That doesn't make sense - if the DHCP server shows them allocated that means the AP requested the IP!

| [2025-09-29 07:51:23.495] [offline-migration][v4] no WLC IP in DHCP option 43 <- option 43 missing from DHCP reply
| [2025-09-29 07:51:23.495] [offline-migration][v4] missing DNS config (server and/or domain) <- DNS config missing in DHCP

It's clear from those logs that your DHCP is not configured correctly - no DNS config and no option 43 configured for WLC discovery.  Refer to the link in my previous reply for the new option 43 configuration.

[Eng.AD27]

still same issue 

still same issue  
ip dhcp pool AA
network 172.18.250.0 255.255.255.0
option 43 hex f305.ac10.fac8.02
dns-server 172.18.250.200
lease infinite

[Mark Elsen]

  - @Eng.AD27                      - Did you restart the DHCP server after making changes ?
                              + Check the logs on the intended DHCP server and  make sure a DHCP request is coming in
                                 from the CW9176 access point.
                              + What is the access point doing if you wait longer then 8 minutes  ?

  M.

[Eng.AD27]

we connect the uplink for standby WLC (CW9800M) with core switch and port down but i receive RX power for this port
if the port will be up after switchover ? 

can you  help me  ? 

[Mark Elsen]

  - @Eng.AD27   This is a new topic , please start a new post for it too and describe the issue in more detail,

  M.