topic Re: Client Stuck in IP learn state cisco 9800 WLC in Wireless

Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Thu, 30 Sep 2021 07:39:15 GMT

Hello Experts,

I am testing Cisco 9800 series WLC with software version 17.3.3, 9115 AP is in local mode.

Issue: When I am using external DHCP server , also added the ip helper address command on upstream switch then all clients stuck in IP learn state.

If I use internal DHCP server then it working.

What could be the issue ?

Thanks

Re: Client Stuck in IP learn state cisco 9800 WLC

Arshad Safrulla — Thu, 30 Sep 2021 07:58:21 GMT

Is the WLC you are testing is a physical WLC or virtual? Did you check whether the DHCP discover messages are received by the upstream switch? You may do a PCAP or a debug if possible to check. Also post the upstream switchport config to the WLC (do not use any native VLANs)

Re: Client Stuck in IP learn state cisco 9800 WLC

Mark Elsen — Thu, 30 Sep 2021 08:05:33 GMT

- You may have some radioactive-trace (client debugging) . which you can let analyze with :

https://cway.cisco.com/tools/WirelessDebugAnalyzer/

Re: Client Stuck in IP learn state cisco 9800 WLC

Sandeep Choudhary — Thu, 30 Sep 2021 08:12:29 GMT

Disable IPv4 DHCP Required and try again!

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Thu, 30 Sep 2021 08:58:56 GMT

Its a physical WLC and no native vlan configured.

Here is the config:

interface Port-channel3
description *** WLAN2 ***
switchport trunk allowed vlan 180-195,172
switchport mode trunk
ip dhcp snooping trust
!
interface GigabitEthernet1/0/4
description *** WLAN2, Port0 ***
switchport trunk allowed vlan 180-195,172
switchport mode trunk
channel-group 3 mode active
ip dhcp snooping trust
!
interface GigabitEthernet2/0/4
description *** WLAN2, Port1 ***
switchport trunk allowed vlan 180-195,172
switchport mode trunk
channel-group 3 mode active
ip dhcp snooping trust

Thanks !

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Thu, 30 Sep 2021 09:01:02 GMT

Yes I did try but still not successful.

Re: Client Stuck in IP learn state cisco 9800 WLC

Sandeep Choudhary — Thu, 30 Sep 2021 10:28:30 GMT

I tested in my lab and it worked for me .

Please do these and test again:

1. Uncheck the box for IPv4 DHCP Required

2. Enter the correct DHCP server IP Address

if still not working then save the config and reboot WLC.

Re: Client Stuck in IP learn state cisco 9800 WLC

Arshad Safrulla — Thu, 30 Sep 2021 10:30:04 GMT

Did you try disabling IP DHCP snooping for the Wireless VLAN's. (not adding ip dhcp snooping trust, remove VLAN's from ip dhcp snooping) Also if you have ARP inspection disable that as well for the wireless VLANs. Also check on the switch logs and if possible run a debug or PCAP to see DHCP discover packets from the client is hitting the Gateway.

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Thu, 30 Sep 2021 11:59:49 GMT

disabled both (DHCP snooping & ARP inspection)...still same issue

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Thu, 30 Sep 2021 12:02:11 GMT

NO its not working.

Re: Client Stuck in IP learn state cisco 9800 WLC

JPavonM — Thu, 30 Sep 2021 13:30:37 GMT

Is there any firewall that may be filtering DHCP traffic?
Do you have SVIs created on WLC for those VLANs where you want DHCP to be received? Are you setting DHCP source interface?
Have you tried a monitor session to capture UDP traffic in Po3 and check if all DORA process is there, or al least Discoveries and Offers?
Can you try to bounce the radio interface to check if this is solved? I mention this because on 17.3.2 there is a bug (CSCvw18047) which is supposed to be fixed in 17.3.3 and that is the observed behaviour, and the workaround to solve it.

HTH
-Jesus
*** Please rate helpful responses ***

Re: Client Stuck in IP learn state cisco 9800 WLC

Sandeep Choudhary — Fri, 01 Oct 2021 06:18:01 GMT

did you try to upgrade the software to 17.6 and try again

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Fri, 01 Oct 2021 06:19:36 GMT

1. Yes its there but client is getting IP when they connect with old WLC"2504"/AP but not with 9800 series.

I also created dhcp scope on switch itself for testing where WLC is connected....still not working.

2. yes i did and also using the source interface

3. no I did not try..., FYI: If I use internal DHCP server then its working but not with External.

4. Tried still not working

any other ideas ?

Re: Client Stuck in IP learn state cisco 9800 WLC

Arshad Safrulla — Fri, 01 Oct 2021 06:32:36 GMT

I think you can go confirm the below;

Make sure that the Layer 2 vlans are create

vlan 180-195,172

If there is any SVI's for user VLAN's delete them, unless you need mdns or dhcp relay you really dont need any SVI's for user vlans.In the upstream switch configure the IP helper address under the interface.

Most importantly as @JPavonM mentioned please check the PCAP, if the upstream switch is IOS-XE you can run it in the switch itself, if not you may have to use SPAN. Alternatively you can use PCAP feature in 9800 (not AP PCAP).

!
Also make sure that no DHCP server IP address is configured under the policy profile. And use the VLAN ID is configured under the policy profile.

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Fri, 01 Oct 2021 07:37:48 GMT

let me try this

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Fri, 01 Oct 2021 07:38:16 GMT

ok I will try this and let you know.

Re: Client Stuck in IP learn state cisco 9800 WLC

ittechk4u1 — Fri, 01 Oct 2021 12:27:04 GMT

So finally these changes did the trick:

1. Upgrade to 17.6.1 version

2. Removed SVI form WLC

3. IP helper command is on upstream Switch.

Thanks all for your help.

Re: Client Stuck in IP learn state cisco 9800 WLC

Sandeep Choudhary — Fri, 01 Oct 2021 12:37:17 GMT

Glad to help and thanks for posting the workaround.

Re: Client Stuck in IP learn state cisco 9800 WLC

kagiso — Thu, 13 Jan 2022 12:03:59 GMT

This was very helpful! Thank you for sharing. I'm running 17.3.4c and have spent hours troubleshooting. The solution for me was to remove the dhcp server address from the wlan policy.

Re: Client Stuck in IP learn state cisco 9800 WLC

billydailey — Wed, 07 Jun 2023 20:12:13 GMT

where did you do these at?