Programming a DOS Twitch Bot: Part 11
Channel: Jookia
Date: 2021-10-14

Today we debug packet fragmentation.

This video may include adult language and humor.
See more at https://twitch.tv/jookia2
Streamed on 2019-12-29.
All original content in the video is licensed CC0 by me.

Timestamps:

00:00:00 Introduction
00:01:00 Removing sslchat.sh
00:08:00 Figuring out TCP fragmentation
00:15:45 Echoing each packet
00:31:20 Testing packet echo
00:32:35 Printing both incoming and outgoing packets
00:35:14 Manually testing packet printing
00:36:05 Experimenting with buffering
00:50:30 Planning line buffering
00:54:48 Debugging why it can't send some outgoing packets
01:01:33 Investigating MTU values
01:31:50 Investigating TCP values
01:38:00 Investigating TCP and IP fragmentation
01:50:15 Investigating mTCP's packet handling
01:55:30 Investigating DOS packet drivers, more mTCP investigation
02:12:05 Explaining how mTCP will accept packets over the MTU
02:14:45 Demonstrating that long packets aren't split properly
02:17:10 Brute forcing good packet lengths
02:21:10 Succeeding in splitting packets
02:25:45 Investigating mTCP's MSS size handling
02:30:25 Investigating Slirp's TCP handling
02:43:06 Trying to jump ship from Slirp
02:49:35 Trying to jump ship to DOSBox-X's NE2000 mode
03:02:50 Investigating QEMU's slirp code
03:15:40 Trying to set the MTU in slirp
03:22:20 Investigating why some incoming packets are dropped
03:32:10 Documenting discovered bugs and issues