For homelab, start with the absolute basics - setup a firewall, and make sure you understand how it works! Map out your network topology, even if it is just your DSL box, router & your PC + printer with a raspberry pi (or 2) for your project.
Hehe, yeah, but even here I run into a large forest of terms and concepts. For example (the questions are only examples of things I stumble upon in this process, not questions addressed at you): “Setup a firewall” - on my server or on the router? Or both? And since my router is provided by my ISP which has its settings exposed through their online portal (which I hate the thought of), how does that factor in? What use is a router firewall if someone gains access to this portal and can configure at will? Can I set up the router in bridge mode and incorporate my own router, and thus have complete local control of my network? Couldn’t someone simply deactivate this in the online portal if they gained access there? And if I open ports in the firewall for a specific application, what risks am I running outside of exploits in the applications themselves? For example, I have opened a port in the router settings for torrenting Linux ISOs (for a specific local IP) - could traffic through the same port be used to compromise the network in other ways? etc. etc.
Suddenly I have fifteen questions. So when trying to research the answer to these questions, I often get slapped with five concepts I either barely have grasp of or don’t know at all in one sentence that tries to explain what is going on. It’s not that it is impossible to learn this way, but it tends to quickly become overwhelming, and I run into explanations of concepts I don’t have enough prerequisites to learn properly yet. Which is why I am trying to get a coherent introduction to all the topics in a sensible, curated way to beef up my understanding of it, so that the research process becomes easier.
For more depth, but not crazy detail, try the O’Reilly books or similar on networks & related security topics (there are a few!)
Cheers, I will have a look to see what I find :) Sounds very much what I am looking for.
One more thing - install Wireshark and get a real-time view of what your network is doing. Massively helpful tool.
I have been meaning to install it to learn more about the structure of the packages that are sent and received. Thanks for the reminder.