How do I prevent disconnection due to Error BadMessage?

Some of our players are being disconnected partway through a game. Logs show the client disconnects with NetworkError.BadMessage, and then the server reports them as timing out shortly after. There seem to be no other relevant logs.

According to my research, BadMessage means the client received a non-data packet, probably due to a rare packet corruption. I know there's no avoiding that, but it why does it force my client to disconnect? Can I make it just ignore bad packets?

Using Unity 2017.4.1 LTS.

 

Hey cracknell_unity, I just found this thread after googling for this exact problem.
Have you been able to find a workaround for this? I am having the same issues atm (Unity 2018.2.11f1), and havn't figured a way around it so far. :-/ right now I am studying the documentation of custom ConnectionConfig to see if maybe some settings there could help, but I suspect anything that could be done there would only change the threshold of when the error will occur (at best) and not completely remove it...

 

@throzen Unfortunately no I wasn't able to find a workaround, there are still a decent number of our players disconnecting for this reason.

I suspect there isn't going to be a fix, as UNet looks to be mostly abandoned now: https://blogs.unity3d.com/2018/08/02/evolving-multiplayer-games-beyond-unet/

 

UNET's LLAPI uses UDP, which means that messages will be dropped and all kinds of weird things will happen.
It might be a LLAPI bug too, but you probably won't see a fix at this point and you won't be able to fix it yourself, since it's closed source.

Unity's latest UNET version can use different low level transports now. You could try another UDP transport, or make your own, or consider TCP (where you won't have to worry about lost packets). Depends on the type of game you want to make too.