Windows Keeps Losing Ethernet, Switches to WiFi

[metaleggman]

So I've been running into an odd issue: my office desktop PC keeps losing internet access over ethernet, and has to switch to my WiFi 6 adapter.  I currently have ethernet by way of a Netgear R7000 set to bridge mode connected to my Netgear RAX120.  This is also how I have my homelab server/NAS (TrueNAS Core 12 with SyncThing plug-in and pi-hole VM) connected to the network; Both are connected directly to the R7000.  My server/NAS doesn't have any issues staying connected to the network/internet.

What I'm trying to figure out is whether this is some router issue or an issue with Windows 10, the OS running on my PC.  I'm currently on Windows 10 Pro Insider Preview 10.0.21322.  The ethernet adapter is a Realtek Gaming GbE Family Controller on my Asus Tuf Gaming Plus, and the Wi-Fi 6 AIC is an Asus AX3000.  Even though I've been thoroughly impressed by the speeds on WiFi 6 over the distance (and obstacles through which) I use it, I still prefer the bridged connection because it tends to be more stable, and hits higher speeds despite being WiFi 5, in terms of maintaining throughput to and from my server (it too has Gigabit ethernet ports, and they're acting in a fail-over capacity).  I've tried different cables and still have the same problem.  I assume part of why it was working so well previously is that the 3 antennae on my R7000 are more powerful than the two on my AX3000.

Does anyone know what logs I could look for in Windows 10 to see what's happening during the hand off from ethernet to WiFi to see what might be going on?  It's only been happening recently, so I'm guessing it's some sort of Windows or driver issue that will eventually resolve itself (as usually happens on dog food builds, which I guess I prefer to having some big issue on a stable build staying for months or weeks).  That being said, I'd like to try and see if I can troubleshoot this somewhat.  Part of the reason is because I'm currently transferring all my files from the server to my PC so I have an on-site backup of sorts, as well as to back it up to the cloud.  However, with about 7 TiB of data left to send, everything runs a helluva lot faster over the bridged connection (possibly because it's bypassing the wireless aspect all together) than WiFi 6.  Currently, I'm getting about 100mbps from the server, whereas before I was getting at least 300mbps (I think that's more or less the limit of my spinning rust; internet speeds both over the Wifi 5 bridge via ethernet and the WiFi 6 adapter were about 5-600mpbs down iirc).

 

Here's the obligatory MS Paint network topology map:

Spoiler

 

[Skiiwee29]

When it happens again, open command prompt and check your network adapter with ipconfig /all and see if your ethernet adapter is still up and showing a valid IP or if it shows nothing. 

[Kisai]

I'd suggest getting a copy of the settings when it's connected to different router's and compare if TOE (Tcp offload engine) or Jumbo Packets are enabled on one and not the other.

 

[Moonzy]

Last time I had this issue, I limited the speed to 100mbps instead of the default 1gbit in the adapter settings

 

Seems to me somewhere in the chain is unstable, for me it was the cable but you tried a different one so -shrug-

[metaleggman]

19 hours ago, Skiiwee29 said:

When it happens again, open command prompt and check your network adapter with ipconfig /all and see if your ethernet adapter is still up and showing a valid IP or if it shows nothing. 

Check Attachments

 

First log is for ipconfig /all when I was on WiFi (post_switch_to_wifi_log01.txt).  Then I disabled the ethernet adapter and enabled it again, which gets it working.  Values for ipconfig /all shown in pre_switch_to_wifi_log01.txt.  Then when it borked and switched back to WiFi, I did ipconfig /all once more (post_switch_to_wifi_log02txt.txt).  Looking at the files in WinMerge (3-way comparison is freaking neato), I don't see any significant differences.

This may be what @Kisai was discussing.

 

18 hours ago, Kisai said:

I'd suggest getting a copy of the settings when it's connected to different router's and compare if TOE (Tcp offload engine) or Jumbo Packets are enabled on one and not the other.

 

I only saw a few options for offloads in the ethernet adapters configuration, but they were all fully enabled.  Jumbo Packets was disabled, but enabling it didn't help (I'm also unsure if either router supports Jumbo Packets).

 

 

18 hours ago, Moonzy said:

Last time I had this issue, I limited the speed to 100mbps instead of the default 1gbit in the adapter settings

I guess it's worth a shot.

 

[metaleggman]

I did look at the Windows Event viewer and found some interesting stuff though, specifically a Server Error with EventID 2505.  It looks related to NetBIOS, which means it's possible it's my SMB share that's messing with it. Description of EventID here.

network_logs.csv

[Kisai]

3 hours ago, metaleggman said:

I only saw a few options for offloads in the ethernet adapters configuration, but they were all fully enabled.  Jumbo Packets was disabled, but enabling it didn't help (I'm also unsure if either router supports Jumbo Packets).
 

Ok, so your WiFi adapter completely disappears even when the wired connection is available. That's actually normal in laptops that are told to turn the WiFi off to save power when connected to a wired connection/docking station. 

 

So that means something is actually causing the wired ethernet to drop carrier long enough for this switch to happen. The event log is actually pointing to the Hyper-V (virtualized adapter), which means that it's possible that the wired adapter is being reassigned to the virtual machine for some reason.

 

If you are actually using Hyper-V (eg VirtualBox, Bluestacks, MEMU, etc) you might need to fiddle with the settings so that it emulates a network adapter rather than reassigns it. Though I reasonably suspect this is not the problem, as I've never had that problem with VirtualBox or MEMU. 

 

As a way to determine if the cable is damaged or too long, force the wired adapter (at either end) to operate in 100Mbit mode and see if it does the same thing. It could be as simple as aggressive power management (which actually saves power by lowering the link rate) to having a kink/bend in the ethernet cable. 

[metaleggman]

1 hour ago, Kisai said:

Ok, so your WiFi adapter completely disappears even when the wired connection is available. That's actually normal in laptops that are told to turn the WiFi off to save power when connected to a wired connection/docking station. 

 

So that means something is actually causing the wired ethernet to drop carrier long enough for this switch to happen. The event log is actually pointing to the Hyper-V (virtualized adapter), which means that it's possible that the wired adapter is being reassigned to the virtual machine for some reason.

 

If you are actually using Hyper-V (eg VirtualBox, Bluestacks, MEMU, etc) you might need to fiddle with the settings so that it emulates a network adapter rather than reassigns it. Though I reasonably suspect this is not the problem, as I've never had that problem with VirtualBox or MEMU. 

 

As a way to determine if the cable is damaged or too long, force the wired adapter (at either end) to operate in 100Mbit mode and see if it does the same thing. It could be as simple as aggressive power management (which actually saves power by lowering the link rate) to having a kink/bend in the ethernet cable. 

So I ended up disabling WSL as a feature, and even disabled SVM in bios, and that didn't change anything.  Neither did anything related to ethernet and power.  What did fix it, which relates to the event viewer errors I mentioned, was disconnecting my SMB share.  Clearly some sort of NetBIOS code was changed during the last update which borked SMB shares in some way, or at least a previously set one.  Will be establishing a new connection at some point here and seeing what happens.

On one hand, I'm glad to have figured out the problem, on the other though, I need access to my damn NAS lol.

[metaleggman]

Crap!  I woke up and it's messed up again haha!  I made my reports in the Insider Feedback Hub, so hopefully this will get addressed next release.

Edit:
So final update, in case for some weird reason someone sees this in the future.  It turned out the update borked the ability for you to assign the same network share as an admin network share (for higher privileged apps) and a user network share.  It took re-installing windows twice to figure this out, and since I've set one as one drive letter, and another as the other, it's been working perfectly.