topic C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired) in Wireless

C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired)

viraj patil — Sun, 24 Dec 2023 08:02:26 GMT

Hello Team,

we have replaced 90 access points till now and they connected as well with WLC. But for 02 access points, it's giving the error of "DTLS Handshake expired". Please help to resolve this issue.

WLC Model = C9800-L-F-K9

AP Model = C9120AXE & C9120AXI

WLC Version = 17.3.6

Re: C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired)

balaji.bandi — Sun, 24 Dec 2023 09:23:33 GMT

Hope i take this as new AP ?

Can you do Factory reset and try to re-join

Also connect console cable and post complete boot logs here to understand the issue ?

what Version of AP - is some mode of the AP shipping later 2022 (i dont remember) need new code 17.9.4a on WLC ( also suggest to upgrade to new code on WLC is advised all the time for better bug fixes)

check some filed notice :

https://www.cisco.com/c/en/us/support/docs/field-notices/639/fn63942.html

https://www.cisco.com/c/en/us/support/docs/field-notices/724/fn72424.html

Re: C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired)

Mark Elsen — Sun, 24 Dec 2023 15:29:19 GMT

- Go for 17.9.4a = recommended release ,

Re: C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired)

Scott Fella — Sun, 24 Dec 2023 23:01:45 GMT

Here is a nice guide to help with ap's not joining issues:

https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/218396-troubleshoot-catalyst-9800-ap-join-or-di.html

Re: C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired)

Rich R — Thu, 04 Jan 2024 16:37:17 GMT

If the APs have old version of software installed they might not be able to join to the WLC.

As others have said upgrade WLC to TAC recommended version as per the link below.

You might also need to upgrade the AP software manually before it can join - for 17.3.6 that would be 15.3(3)JPJ9:
https://software.cisco.com/download/home/286322988/type/286288051/release/15.3.3-JPJ9

Re: C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired)

alaangaldino — Tue, 25 Feb 2025 11:55:25 GMT

Follow the procedure for correction

For AP Models 2802, 3802, 4800, 9105, 9115, 9120

While connected to the console, power cycle the AP.
During bootup, when you see Hit ESC key to stop autoboot, press the Escape key
This should bring you to (u-boot)> prompt.
Run these commands

(u-boot)> ubi part fs

(u-boot)> ubi remove part1 (or part2 if corrupted image is in part2)

(u-boot)> ubi create part1 (or part2 if corrupted image is in part2)

(u-boot)> boot

Re: C9120 AP Not Joining C9800-L-F-K9 WLC (DTLS Handshake Expired)

Rich R — Tue, 25 Feb 2025 15:06:46 GMT

@alaangaldino those instructions are only relevant if the active software partition is corrupted - which should not be the case with a new AP. And in that case those instructions alone may not be enough to guide the user to resolving the issue. Those instructions are copied from the technote at https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/220443-how-to-avoid-boot-loop-due-to-corrupted.html and should be read as part of the entire technote for full understanding of the issue, and the resolution, and the alternative methods for resolving it - if corrupted active partition is the root cause of the problem. Note the link to the technote is already included in the links in my signature on my previous reply above.