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MC-93515

Cannot connect to LAN worlds that send huge network packets / Badly Compressed Packet

When connecting to a LAN world that is rather large, the host will send huge network packets to its clients, and there appears to be a 'protocol maximum,' which makes properly connecting to large LAN worlds impossible.

Steps to Reproduce:
1. Host a LAN world that is large and well played on. (E.g. a well-played survival world, or an adventure map).
2. When other players attempt to join, they will get an error message like this:
Internal Exception: io.netty.handler.codec.DecoderException: Badly compressed packet - size of 2487995 is larger than protocol maximum of 2097152

It is worth noting that you can properly connect to a LAN world if the world has just recently been created, probably because it is newly generated and therefore is not sending very many network packets.

This problem must be fixed. It is not a problem with the network we were using - we tried it at two different places and came up with the same problem. Therefore it must be a problem with Minecraft.

Comments 11

Not just lan, servers as well.

Launcher Log:
"[00:34:19] [Client thread/INFO]: Connecting to play.hypereclipsemc.com, 25565
[00:34:19] [Server Connector #4/ERROR]: Couldn't connect to server
java.net.ConnectException: Connection refused: play.hypereclipsemc.com/52.35.149.80:25565
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) ~[?:1.6.0_65]
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:599) ~[?:1.6.0_65]
at io.netty.channel.socket.nio.NioSocketChannel.doFinishConnect(NioSocketChannel.java:208) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
at io.netty.channel.nio.AbstractNioChannel$AbstractNioUnsafe.finishConnect(AbstractNioChannel.java:287) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:528) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:468) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:382) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:354) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) ~[netty-all-4.0.23.Final.jar:4.0.23.Final]
at java.lang.Thread.run(Thread.java:695) ~[?:1.6.0_65]"

Server Info:
15w47c,
Java: OpenJDK Runtime Environment (build 1.8.0_65-b17)

Client Info:
15w47c,
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-462-11M4609)

Error displayed:
"internal exception io.netty.handler.codec.decoderexception: Badly compressed packet - size of {2102579} is larger than protocol maximum of 2097152"

I will now go test for 15w49b.

May be world file. Wasn't having this problem before.

New world on 15w47c works, back to old world, doesn't work.

If this only affects one specific world you'll have to attach it here if you want us to help you.

It still affects the same world in 15w50a. Some other worlds work, though.
The world that doesn't work is an unfinished adventure map, and so I cannot attach it publicly. Do you know how I could attach it so only moderators and other people that can be trusted see it?

1 more comments

My own Packet Error thread was marked as a duplicate of this.

Has anyone found a fix? This seems like a huge bug - a white elephant in the room, that Mojang or Microsoft is just ignoring, however many people it effects.

It only takes 3 people to prove a disease or genetic disorder in Science, and we have more than 3 duplicates listed here.

Is there any solution?

( There are more bug posts that haven't been linked to this one. Google it, I came across quite a few, some marked as Invalid and others as Duplicates and yet others as "Contact Mojang Technical Support". This problem is being deliberately avoided.

Is this still an issue in the most recent versions (currently that is 1.10.2, or 16w43a) of Minecraft? If so, please update the affected versions and help us keeping this ticket updated from time to time. If you are the owner/reporter of this ticket, you can modify the affected version(s) yourself.

Yes it is still a problem in 1.10.2 my friend tries to join me over lan, and he still gets this.. yes we've tried everything

This is still an issue in the most recent version of the game, 1.19.2, 5 years later.

This report is currently missing crucial information. Please take a look at the other comments to find out what we are looking for.
If you added the required information and a moderator sees your comment, they will reopen and update the report. However, if you think your update to this report has been overlooked or you want to make sure that this report is reopened, you can contact the Mojira staff on Discord or Reddit.
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Cavinator1

(Unassigned)

Unconfirmed

ConnectionRefused, LAN, LANserver, LANworld, Network, NetworkPacket

Minecraft 15w47c, Minecraft 15w49a, Minecraft 15w49b, Minecraft 1.8.9, Minecraft 15w50a, Minecraft 16w02a, Minecraft 1.9 Pre-Release 1, Minecraft 1.9 Pre-Release 2

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