ARP resolution failures AX211, Windows 11 (21H2, 22000.795)

[lgcvsa]

I have built a new PC using a Gigabyte Z690 UD AX motherboard with integrated Intel 6E AX211 160 Mhz wireless network adapter, and I have been experiencing frequent strange network failures. I am using driver version 22.120.0.3, which the Intel Driver & Support Assistant reports are being up-to-date.

What is happening is that the computer will seem to lose its connection to the Internet, but upon further investigation, I'm able to ping my router and sites on the Internet, but I have lost DNS resolution. I am running a private Pi-hole DNS server on a Raspberry Pi 3B+ under Raspberry Pi OS. 

When this happens, I can no longer ping the DNS server, and if I open a terminal and check the ARP cache on the Windows machine, there is no entry for the IP address of the DNS server., although the ARP table entries for my router and printer and other devices are still there.

Without the ARP resolution, of course, there's no way for my new PC to find the DNS server even by IP address. So that indicates to me that the ARP resolver on my new PC is failing in some odd fashion where it seems to only lose the ARP data for my DNS server, which really makes no sense, and I know it's not the Pi or my router, because all other machines on my network continue to operate normally.

Disconnecting and reconnecting the wireless connection does not fix the problem. Disabling and re-enabling the AX211 doesn't fix the problem. Rebooting the router doesn't fix the problem. Rebooting the DNS server doesn't fix the problem. Changing the drivers to the ones released by Intel directly or the ones from Gigabyte doesn't fix the problem. Restarting the PC does not fix the problem.

The only thing that fixes this problem is completely shutting down the Windows PC and powering it off, then powering it back on and allowing it to boot up. Then everything is working again, at least until the next time it decides to simply quit working. These failures are happening at least once a day.

As a workaround, I disabled the AX211 and installed an older Linksys WUSB6300 (v1) adapter I have, using the driver provided by Microsoft, and the system has been stable for several days.

Now, it did occur to me that there is one other aspect of my network that might be relevant. My WiFi router is a Motorola combination cable modem and router, a Motorola MG7540, which is an AC1600 router, while the AX211 is an AX adapter. The Linksys WUSB6300 is an AC1200 adapter.

I bought the AX version of the motherboard because the specifications said that the AX version supported AC, as well, but the AC version (which has the Intel Wi-Fi AC 9560 chipset) does not support AX, as well, and I wanted to be sure I was future-compatible.

Today, I removed the Linksys adapter from the PC, and re-enabled the AX211, but this time, I went into the driver settings, and changed the "802.11n/ac/ax Wireless Mode" to "3. 802.11ac". I am not sure if this will improve things, but I thought it was worth a try. Who knows how long it may last. I will post updates if it continues to fail, or after enough time has passed to convince me it's stable, if it doesn't fail.