Hi,

 

i read that the problem is caused by Bungeecord and has to do with some fields in the handshake protocol.

I wonder what Forge Client/Server have to talk about, if the server only uses server mods and the client only client mods. Is it possible to not exchange any information about forge/mods and behave like a normal vanilla client and will this also resolve the problem (at least for "vanilla" server)?

There is no way to tell if the server is vanilla or not. We use a field in a way that is publicly acceptable and expandable to tell the server that we are a modded client. if it wasn't for Bungeecord doing it incorrectly everything would be fine.

Basically there is a solution in place for BungeeCord/Spigot they need to update.

 

I assume it cause problems if you join a modded server wihtout exchanging some infomrations about forge and the mods?

But in the case you won't join a modded server anyway, it would be nice to force forge to behave like a vanilla client without exchanging any informations. See it as a privacy setting

Quite literally the ONLY thing that you tell the server on a Forge client when connecting that isn't vanilla is "FML\0" Literally. That is a identifier added to the handshake method that say "Hey if you're modded then we can do our handshake"

So no, it's not a 'privacy' issue.

It's a your server is forcing protocol changes onto the clients in a incompatible fashion and they should stop being stupid.