Rex: Minecraft packet sniffer

Rex is a Minecraft proxy server that can identify, print and dump packets that pass through it. It might be a useful tool if you're interested in how Minecraft works or are writing your own client/server.

Features

These can be turned on/off and filtered by packet type:

• Print the direction, id and name of packets that pass through the proxy
• Print hexdumps of packet payloads
• Save payloads to disk
• Authenticate connecting users
• Connect to online-mode servers (requires an account)

Limitations

These might be fixed at some point.

• No support for sniffing packets in protocol modes other than "play". Both client-side and server-side login (whether online-mode or not) take place in isolation. Support for dumping handshake/status/login packets should be possible in offline-to-offline proxies, but isn't available yet.
• No "transport-level" information. Rex won't give you information about encryption, compression, etc.

Requirements

• quarry

Sample output

# Print the ids and names of upstream (client->server) packets
$ python rex.py -c 127.0.0.1:25566 -d up
PacketSnifferBridge{barneygale} | INFO | --> play 0x15 Client Settings
PacketSnifferBridge{barneygale} | INFO | --> play 0x17 Plugin Message
PacketSnifferBridge{barneygale} | INFO | --> play 0x06 Player Position And Look
PacketSnifferBridge{barneygale} | INFO | --> play 0x03 Player
PacketSnifferBridge{barneygale} | INFO | --> play 0x00 Keep Alive
#-snip-

# Hexdump the "Player List Item" packet
$ python rex.py -c 127.0.0.1:25566 -x -p play 38 down
PacketSnifferBridge{barneygale} | INFO | <-- play 0x38 Player List Item
00000000  00 01 fa de 3c 17 42 aa  3e c3 af 21 3b 62 b6 65  |....<.B.>..!;b.e|
00000010  67 a1 0a 62 61 72 6e 65  79 67 61 6c 65 00 01 00  |g..barneygale...|
00000020  00                                                |.|
00000021
#-snip-