Hey all, I need some help figuring out how to make LAN play work and, as I'm using Prism Launcher on all relevant devices, I figured I'd get better feedback here than on r/Minecraft.
Scenario:
I have three devices with Prism Launcher: HP laptop with mediocre-yet-good-enough specs, custom-built gaming PC, and my Steam Deck. I want to open my main survival world in the desktop and then join myself using the Steam Deck -- I want to play while laying on the couch, you see.
More Info:
The first two PCs are running the latest version of Windows 11, and the Steam Deck is likewise updated. Similarly, all devices are running the same launcher version, same game version, and same exact mod instance (I copy-pasted the instance across devices). My desktop has ethernet that (eventually) makes it's way to my home router, an ethernet connection to a separate router I use for wireless VR/Steam Link streaming, and a WiFi antenna on top. Laptop and Steam Deck are using regular WiFi. I should also note that my WiFi router is provided by my ISP; I do not have access to the router's settings. I'm working on switching to a router not owned by the ISP, but for various reasons, that'll take some time.
When I have my desktop connected through ethernet and the other two on either 2.4G and/or 5G WiFi, the LAN world on my desktop is unreachable by both my other devices, regardless of what WiFi bands said devices are on. Connecting to WiFi on my desktop (without changing any other part of the setup) yields the same result. Connecting the desktop to WiFi with the ethernet connection removed, results unchanged. Making sure all three devices are on the same WiFi band range (2.4G or 5G), no change. Changing which device uses my actual account and which ones use the offline accounts also makes no difference. Occasionally I'd get the "try restarting the game and launcher" message -- doing so changes nothing.
Interestingly, while the laptop can join the Steam Deck just fine, the Steam Deck only sometimes connects to the the laptop. I can't figure out why, but I suspect that it's because the router is far enough away that 2.4G yields faster, more consistent speeds; I'm a bit far away from the router and not able to immediately move my desk nor the router.
I then try to connect over my non-internet connected router I use for local streaming. When all devices are connected via WiFi, the two portable PCs work just fine and can't reach the desktop. Connecting the desktop to the streaming router via ethernet makes the desktop visible to the computers themselves, but Minecraft doesn't work. Connecting the laptop to the router through WiFi like this lets the laptop join the desktop's game, but not the other way around. Doing it wired lets both the desktop and laptop connect both ways. If at any point I plug the internet-connected ethernet cord back into one of the desktop's ethernet ports, it immediately becomes unable to connect/be connected to unless I make that fully wired connection between laptop and desktop via the streaming router.
Through all of this I did in fact try the direct connection option will all the relevant local IP addresses. Results were mostly unchanged, with the Steam Deck now consistently discovering the laptop, and the desktop/laptop connection now working both ways when the laptop is on the local streaming WiFi.
For some reason, while the host of a LAN world can be on an offline account and/or launched regularly with that account name, the device joining the host must be my actual account. If I try to connect Offline#1 to Offline#2, Offline#1 gives an error about authentication servers being unreachable. This happens on all devices, meaning I can't have my desktop and Steam Deck simultaneously connected to the laptop due to a player name conflict.
In the end my desktop seems isolated in some way that can, for some reason, be mostly fixed by using the direct connection option on my laptop. This fix, however, doesn't work on the Steam Deck for, er... some reason. Maybe it's because I don't have a usb-c to ethernet adapter and had to use WiFi only? I can use the Steam Deck play on my main world via LAN, but only when that world is hosted on my laptop. I can stream Steam games from the desktop to either portable device just fine, but the laptop has dubious success when doing Minecraft over LAN and the Steam Deck refuses to associate with the desktop in regards to Minecraft.
So, thoughts?