Topic: Ethernet port on Switch 2 docks failing for MANY people

@WhiteUmbrella
Righto, I mean, all I'm saying is that you were wrong when you said that "the fault stems from the security measures Nintendo has implemented to lock out third party accessories". Or that "the Switch 2 itself is rejecting the ethernet connection specifically". And to back your claims you cited the LTT video which, for the interests of those browsing, actually outlined their testing here:
https://www.lttlabs.com/blog/2025/08/30/nintendo-switch-2-dock

Notably they ran 8 tests of various configurations. Two different power adapters, the Switch 2 adapter and a 100W ugreen power adapter. Both of which worked fine and negotiated a 15W charge rate. Then they tested three different display devices. The Switch 2 Dock, which worked fine. A third party dock claiming to support the Switch 2, S3 Max Dock, which also worked fine.

The device they tested which failed was a 4K Proart Monitor. It failed to negotiate a display signal. Nothing at all to do with the official dock or USB device support, the topic of this thread. The display just kept asking for the devices to swap roles in the negotiation and the Switch 2 refused. So the two devices failed to establish a connection. Nothing at all to do with USB device support, which is what would impact the Ethernet port

Also, notably, as I was saying the technical article is far less bombastic than the video "Nintendo's Greed could Change the Tech Industry". The article itself concludes:

Nothing in the LTT video you cite suggests what you are saying is happening. Nowhere does it show they're abusing Vendor Defined Message, nowhere does it suggest encryption or security or anything like that. It says, as I said, that the Switch 2 negotiates the display output capabilities required of the dock sloppily which seems to break compatibility with most third party docks. To quote my first post directly

And in any case, this thread is about issues with the official dock, which is almost by definition unrelated to the topic you brought into this thread. Because the official dock negotiates its capabilities fine. All you've achieved here is to bring this topic further away from answering the thread topic. The Ethernet adapter on the official dock misbehaving for some people. Something I've also seen

Some actual on-topic constructive thoughts/theories given what I've experienced with Nintendo's hardware behaviour on networks. And also what some have said in this thread and other threads like this on this specific issue:

1. Possibly there's some hardware fault. A dodgy batch of Ethernet controllers or something. This doesn't quite make sense because some have reported that the issue resolved after rebooting or after a firmware update. Or that it worked in one environment but not another. It also doesn't mesh with my own experience, why does mine work fine but my sister's does not even though we got them at the same shop on the same day. But it's still possible

2. There's some specific environment setup the Switch 2 doesn't like over Ethernet. Perhaps it's particularly picky about CG-NAT when you're on Ethernet but is more tolerant over WiFi. Who knows. Networking is kinda notorious for this kind seemingly inexplicable behaviours with some devices

3. Perhaps there's a firmware bug of some kind impacting wired connections. Possibly the driver for that network controller in the dock is flakey and prone to crashing. Maybe there's a bug in the Switch firmware itself that's meaning it applies some settings correctly or expects something off. Hard to know but I have seen the Switch and Switch 2 both do this for WiFi. I'll edit something like band-steering and it'll disconnect, expected, but then just refuse to connect again until I delete the config

..... I'll certainly troubleshoot it on my end given, it seems, I have one device that has this behaviour and one which doesn't. I'll report back here if I find anything interesting. Although it may be a while given I'm in no particular rush to go to my sisters with my Switch 2 and spend a day messing around with Switch 2 docks and routers. Especially given that WiFi is not that different from wired for her setup anyways

I made an account to confirm a fix that worked for me. I noticed this problem last week, and have been browsing forums where this is a topic.

I noticed in a few places that some people have found success in making it work again. Here's what I did.

1. Plugged a mobile device with USB C connection into the Switch 2 Dock. I used my iPad 16. I put it in firmly and saw that it was charging, removed after 10 seconds
2. Retried the wired connection via the internet settings

My Switch 2 Dock now picks up the LAN connection

This worked for me, I want to confirm cos before I tried it I thought that advice might have been some playful trolling. I was very surprised to see it connect again after I tried.

I wanna know if this works for others!

@JJ43 The reason this fix works is because the Switch 2 dock’s LAN adapter is handled through the dock’s internal USB-C controller. Sometimes that controller gets stuck in an invalid handshake state and stops detecting the Ethernet hardware entirely.

Plugging in a certified USB-C device like an iPad or phone forces the dock’s USB-C controller to renegotiate power and data lines to full spec, which “resets” the handshake logic. Once that happens, the dock can see the LAN adapter again, so the Ethernet connection starts working.

It’s not a permanent hardware repair, but rather a firmware level reset triggered by the proper USB-C negotiation sequence.

@JJ43 @powereat I tried docking two different android type-c devices, one of them being a samsung galaxy tab s6 lite, and neither of them showed any sign of charging or recognition in any sense which I'm assuming is the sign that it didn't work. is an apple or some other branded device what does it or could I just be an outlier?

@videogamesreallife I can only assume you’ve not plugged it in far enough. There’s a spring mechanism in the dock where the Switch 2 presses down, exposing the USB Type-C male part. It’s tricky, but you have to be persistent and try. I used a Huawei phone. The moment you see the dock charge your device, leave it for ten seconds, then remove it.

@skywake super useful, thank you! Could you share the source of the CG-NAT discussion?

Been using the ethernet since I got my Switch 2 in late June. Works perfectly.

@vio Mine works fine in non-CG-NAT environments, less so in CG-NAT (Metronet).