The internet is a complex network of routers, switches, and computers, and when we try to connect to a server, our packets go through many routers before reaching the destination. If one of these routers is misconfigured or down, the packet can be dropped, and we can’t reach the destination.
In this post, we will see how
↫ Sebastian Marinestracerouteworks, and how it can help us diagnose network problems.
I’m sure most of us have used traceroute at some point in our lives, but I never once wondered how,, exactly, it works. The internet – and networking in general – always feels like arcane magic to me, not truly understandable by mere mortals without years of dedicated study and practice. Even something as simple as managing a home router can be a confusing nightmare of abbreviations, terminology, and backwards compatibility hacks, so you can imagine how complex it gets when you leave your home network and start sending packets out into the wider world.
This post does a great job of explaining exactly how traceroute works without overloading you with stuff you don’t need to know.
Good beginner article. I understand everything in there. Now unfortunately, everything is more complicated in the real world. ICMP is blocked by many as its seen as potentially malicious, or at least it was used maliciously in the past DDOS attacks. Some prefer using MTR as its more robust and has more options, like the ability to use TCP to get around ICMP blocking. Usually when diagnosing things, network people want an MTR, I go through heck to get one which points the finger at their equipment, and all of a sudden MTR’s aren’t worth anything to them anymore and they dismiss my findings… Probably because diagnosing glitchy networking equipment is a pain.
For anyone wanting more info on how to read MTR output
https://blog.apnic.net/2022/03/28/how-to-properly-interpret-a-traceroute-or-mtr/#:~:text=Traceroute%20is%20a%20one%2Dshot,is%20the%20tool%20to%20use.
Is a good start.
Be aware that this article is somewhat outdated. It still refers to TTL and the examples are based around IPv4. With IPv6 this value has been renamed to “hop limit” as that was deemed a more accurate name.
With regards to learning more about networking, these kinds of aspects do tend to be covered by computer science curricula. We used the book from Kurose and Ross in university, Computer Networking: A Top-Down Approach Featuring the Internet. If you come across a copy, it would probably be interesting to read. Things are quite logical if you understand the different OSI layers and how they interact.