Yea, their protocol repeats a lot of what the TCP protocol uses. However this isn't necessarily a bad thing. They have, after all, cut down on the number of packets and number of bytes being sent between the client and server (compared to if they used TCP). The protocol just needs some more testing/...

Yep. The TCP handshake ( https://en.wikipedia.org/wiki/Handshaking ) would be extremely easy to implement and would solve the whole issue. Just need to get a dev to actually read this.

Possible solution would be to establish a handshake with the client instead of assuming it is good. Client sends a single packet out, server sends a single packet in reply, client replies to that packet, server starts sending tons of packets to the client. If the client isn't an actual Factorio gam...

Thanks ssilk. I can provide more information, write a script to do this, or test to see if the bug still exists in .13 if you like.

Yep, thats exactly it.

I wrote my own program to act as the server (was easier than writing a program to drop packets). Would you like me to post my code for that? I haven't copied an pasted anything from Factorio's source code but it contains details on how your network protocol works and how the game in general works. T...

The client will hang (as in sit an wait, not doing anything) after a connection to the server is established (that is, once a ConnectionAccept message has been received). If no heartbeat messages or transferblock messages are sent, the client will sit and wait for information from the server indefin...

It doesn't cause any actual issues, but if the platform string is always going to be set to "win32", then there is no point in sending the platform name.

As far as I can tell the session magic isn't currently being used. When a packet is received with a bad session magic, the server logs and error, then proceeds to process the packet. Assuming this isn't a bug, there is no need for the session magic. The ConnectionRequestID should be sufficient to un...

As of right now, when a client sends a connection request to a server, the server sends a large number of packets back to the client. Due to the connection being UDP, this could potentially be used to perform a DDOS amplification attack. Here's how it works: 1. An attacker sends a connection request...

The OP code that starts each network message it two bytes long. There is no need for this; factorio will never have 256 different OP codes, let alone 65536. One byte is plenty.

On all (recent?) 0.12.* versions the ApplicationVerison deserialization constructor isn't properly deserializing the platform string. The string is being transmitted properly, however, the "platform" variable is always being set to "win32". I've tested this on a few versions betw...