Messing with Traceroute

TL;DR: Traceroute is fun tool to investigate how packets travel through the internet. Due to how it's made, we can make traceroute tools show (almost) arbitrary poems. This blog post gives you an idea how. Decades ago, only a bit after I first discovered the internet, I learnt about the traceroute tool. This tool can show you which path your data takes through the internet, on a very low level. You can see which internet service providers your packets travel through, which cities and continents it passes and sometimes you can even make out which specific deep sea cable is being used. Soon after getting acquainted with traceroute, someone (this being more than a decade ago, I don't remember the specifics) pointed out that you could traceroute a certain IP address1 for fun things to happen. But before we get into that… let's look at traceroute in its natural habitat. Table of Contents Traceroute output How traceroute works Messing with traceroute Setting up a playground Inserting a fake…