C9115AXI client problems

[Chris.Mes]

We have two C9115AXI on remote site, with central WLC C9800. These two C9115AXI are connected to switch C9200 (PoE). No other PoE devices on the switch.
They worked fine for a few month, but now we have strange issue, clients on one of the APs can authenticate, get ip address from DHCP, but they get wrong DNS server, because they get the ip-address of the AP1 as DNS. So they are not able to work.
They even can not ping their default-gw. We've done everything, change cables, switchports, reboot switch, reboot WLC, even change the AP1, but with new AP (same model C9115AXI) we've got exactly the same problem.
And the funny thing is, after reboot of the switch, the problem moved from AP1 to AP2.
So it seems, only one of the AP does work at same time.
Any ideas?

[balaji.bandi]

what you see logs on the controller, do you have enough licenses ?

connect the console to AP and post full logs.

[Mark Elsen]

 - Have a checkup of the WLC C9800 configuration with the CLI command  show  tech   wireless , have the output analyzed by  https://cway.cisco.com/tools/WirelessAnalyzer/  , please note do not use classical show tech-support (short version) , use the command denoted in green for Wireless Analyzer.               Checkout all advisories!

 M.

[Scott Fella]

Seems like you have a dhcp issue not really wireless.  When you use dhcp, you either perform a mac address reservation so that your ap's always get the same ip address or you have static and you exclude the ip address of your ap's, gateway and any other devices you might have, like the switch ip as an example.  Devices getting an ip address of your ap or any other device is a problem with your dhcp configuration.

[Chris.Mes · Accepted solution]

Hello!
I think the problem was "Mobility Express", because I also saw additional MAC-address 0000.5e00.0101 on the switch and I saw it in the leases of DHCP. Since I've entered command "ap-type capwap" on the APs they work like expected.

[balaji.bandi]

i was guessing the same, but as per your POST - both are working (but only 1 working at a time) - that made me to ignore that AP not running ME.

that is the reason asked complete logs of AP booting.

any way glad you convert in to capwap to fix.

[Rich R]

Search for other posts about EWC APs unexpectedly switching back from CAPWAP to EWC mode.  Best to re-flash those APs using the recovery software to completely remove EWC.  Also set the option 43 for CAPWAP mode so DHCP always tells AP to use CAPWAP mode.

Note: Mobility Express was the AireOS WLC product on Wave 2 (18xx/28xx/38xx) APs.  The Catalyst 9000 APs run IOS-XE (9800) based EWC for AP.