AX201 Dell Cisco Meraki VPN not passing traffic due to fragmentation

[brainhig]

Multiple Dell laptops with AX201 will connect to Meraki VPN using L2TP and Windows built-in VPN client, but will not pass most traffic. Some websites can be contacted, but most internal connections to corporate resources and RDP servers fail to connect. 

First solution that worked for one laptop was to use a 2019 era default Windows driver for WiFi NIC. 

One laptop exhibited the same symptoms and no driver, Windows, Dell, Intel or otherwise would alleviate the problem. 

It was found that fragmented packets were the cause of the lack of connectivity to resources. Setting a lower MTU allowed packets to flow unfragmented. 

As this setting will get changed if a newer driver is installed in the field for these laptops, this is not a viable solution for the long run. 

Dell informs that they have seen multiple problems with this NIC, though this specific issue is new to them. 

Is this one of the issues Intel is aware of and is in the process of resolving in a future driver version and/or firmware update? Is there a timeline for resolution of issues such as this?

[DeividA_Intel]

Hello brainhig,  

Thank you for posting on the Intel® communities. I am sorry to know that you are having issues with your Intel® Wi-Fi 6 AX201.   

In order to better assist you, please provide the following:  

1. Are the laptops using the original adapter that came pre-installed on the computer or did you change/install the adapter to these ones?  

2. Are all the laptops from the same exact model or are different?

3. What are the models of the laptops where you are having the issues?

4. Is this issue present with just the Intel drivers or also with Dell drivers?

5. Is this issue out of the box or did it start after a system update?

6. Does the issue happen with a different network or router?

7. What is the exact brand and model name of your router/modem?

Regards,  

Deivid A.  

Intel Customer Support Technician  

[brainhig]

Hi David,

Thanks for your response. Let me see if I can cover your questions thoroughly:

1. There are brand new Dell Latitude 5520s, one is a 15 inch screen, the rest are 13. Not hardware modified or upgraded.

2. Same model. All with AX201 WiFi 

3. Dell Lattitude 5520

4. One one machine, problem was resolved by using the Windows in-built driver, version 21.10.2.2 after trying multiple versions of Dell supplied driver and Intel drivers. 

On two machines, no driver from MS, Intel nor Dell would change the symptoms. On one, there was no problem at all and worked with the current Dell driver from last month. 

5. All machines were out of the box Windows installation from Dell, with the latest Windows and Dell updates applied. Up to date as of last week. Behavior the same before and after last updates applied this week.

6.  I tried the Cisco Meraki wireless at our office, one user has an Xfinity router at home, a Centurylink router, a Verizon hotspot, Pixel 3XL hotspot, WiFi at Starbucks. The behavior was the same no matter the WiFi connection. Problems did no exist in office, directly connecting to servers and services on premise. The issue only shows up once connected to the Cisco Meraki VPN (using Windows VPN client over L2TP -- did not try any other protocol)

7. See above. Multiple access points and routers, security, channels. 

I know this doesn't help too much - The only definitive fix I found was changing the MTU to a smaller size. The only concrete clue about where the packets were being held up was on the Cisco Meraki data capture, which showed no packets arriving over the VPN connection when trying to connect to RDP servers in particular from the laptops. 

Let me know if there is anything else I can provide. 

Thanks again!

[Steven_Intel]

Thank you for the information provided.

By any chance, have you tried performing a clean installation of the latest wireless drivers? We would like to try this to ensure everything is updated.

You can try the latest drivers provided by the device manufacturer and also the latest generic wireless drivers (https://www.intel.com/content/www/us/en/download/19351/windows-10-and-windows-11-wi-fi-drivers-for-intel-wireless-adapters.html).

If the issue persists, please take one of the affected machines and download the Intel® SSU https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows- 

Open the application and select "Everything", click on "Scan" to see the system and device information. By default, Intel® SSU will take you to the "Summary View". Click on the menu where it says "Summary" to change to "Detailed View". To save your scan, click on "Next", then "Save". Please attach the file to your reply.

Best regards,

Steven G.

Intel Customer Support Technician.

[brainhig]

Following your suggestion, I have updated one of the machines with the latest Intel driver 22.170.0

I reset all the parameters to defaults including MTU. This driver so far is stable and connects and passes traffic through the VPN. Also this seems to have resolved an issue connecting to one phone's hotspot that wasn't working before. In addition, we tested this driver on on older machine with a 7265 WiFi nic and it seemed to solve some problems we had with that as well.

I will test on at least one of the other laptops we had problems with and report back again. But this looks good!

[Steven_Intel]

We are glad to know the driver has fixed this and other issues so far.

Please let us know of the outcome once you have tested it on the other laptops.

Best regards,

Steven G.

Intel Customer Support Technician.

[AndrewG_Intel]

Hello brainhig

We are checking this thread and we would like to know if you need further assistance. Were you able to test additional systems with driver 22.170.0? If so, did the driver help to solve the behavior?

Best regards,

Andrew G.

Intel Customer Support Technician

[DeividA_Intel]

Hello brainhig, 

I was checking your thread and see that we have not heard back from you.  

I’m going to close your post, but if you need further assistance, please do not hesitate to create a new thread. 

Regards,  

Deivid A.  

Intel Customer Support Technician