How to Learn Networking Roadmap
Networking is hands down the most important thing to understand in security, and still, people just kind of fumble through it. Give yourself the hands on, practical knowledge required so that you can succeed.
This is the official Ropper’s Networking Course:
The course will teach you the base knowledge required to become a networking stud and will guide you through a variety of networking CTF challenges. You will do a bunch of packet capture problems, some packet crafting, and a few other miscellaneous networking shenanigans. It’s hilariously practical, and ignores nearly all the finer parts of networking… sorry, not sorry.
We will spend a little time going over the fundamentals, but most of the time will be wrapping your head around how to make the packets dance and what it looks like going over the wire. If you want an academic view into the protocols and how packets bop around, take a college course or read a book. This course is for rolling up your sleeves and getting your hands dirty.
Like all good things, you just have to spend time doing this. I hand waved the hell out some complexity so eventually you probably should spend more time getting a deeper understanding of what all these things are, but at least you have the important things now.
If you are going for your Comptia Network+, or just want a legit deep dive into Networking, check out Professor Messer’s Net+ Training. It is extremely high quality, and you are now prepared to get everything out of it.
Building a home lab is a great way to get practical knowledge of how computers work together, and how they break. This is the best resource on the topic by a significant margin: Building Virtual Machine Labs: A Hands-on Guide (Second Edition). The author is absolutely awesome and is a supporter of this site.
My favorite resource to actually understand sockets is https://beej.us/guide/bgnet/. This is critical stuff to understand how the operating system interacts with the networking stack, and if you’re doing network programming, that is more important than whatever the network is doing with your packets when you throw them out into the ether.
I am a huge fan of the Cyber Plumber’s Handbook: https://github.com/opsdisk/the_cyber_plumbers_handbook
Self described as the definitive guide to Secure Shell (SSH) tunneling, port redirection, and bending traffic like a boss, this is the book that teaches you to be good at fancy footwork. Also very relevant for offensive security.
Finally, the real answer to this is to look at more pcaps. Whether it is just sitting around capturing your local network, looking at malware c2, CTF challenges, or some of these structured datasets, the more you get your eyes on, the better prepared you’ll be to know normal.