Not necessarily in this order:

1. Learn the OSI and TCP/IP layer models.

2. Learn the fundamentals of IPv4 and IPv6. (Absolutely learn to count bits for IPv4)

3. Learn and understand the use-cases for routers, switches, and firewalls.

4. Learn about DNS. (Domain Name System)

5. Learn about DHCP. (Dynamic Host Configuration Protocol)

6. Learn important Port Numbers for important Services. (SSH is Port 22, for example. The range of port numbers from 1024 to 49151 are "registered ports" that are generally always the same)

7. Learn about address classes. (A, B, C are the main ones)

8. Learn about hardware addresses (MAC address) and how to use ARP to find them.

And more! This is just off the top of my head. Until you've studied a lot more, please, for your own sake, don't open your selfhosted ervices to the wider internet and just keep them local.

And just for fun, a poem:

The inventor of the spanning tree protocol, Radia Perlman, wrote a poem to describe how it works. When reading the poem it helps to know that in math terms, a network can be represented as a type of graph called a mesh, and that the goal of the spanning tree protocol is to turn any given network mesh into a tree structure with no loops that spans the entire set of network segments.

I think that I shall never see

A graph more lovely than a tree.

A tree whose crucial property

Is loop-free connectivity.

A tree that must be sure to span

So packets can reach every LAN.

First, the root must be selected.

By ID, it is elected.

Least cost paths from root are traced.

In the tree, these paths are placed.

A mesh is made by folks like me,

Then bridges find a spanning tree.

— Radia Perlman Algorhyme

Check out Linux Upskill Challenge there's a community on programming.dev [relative link]

It's a bit askew from what you're asking about but very related and a nice onramp to certification options that have some value in the job market.

As a more direct answer, a bit more of a formal approach to learning networking can be persued by following the networking recommendations at Teach Yourself CS

I would suggest more learn by doing approach. Learning OSI model etc is nice, but it is quite jargon :)

Use some old PC as a server, and get some network cards into it, and use it as firewall/router. Route your home network/NAT/DNS/DCHP through it. Raspberry Pi's are nice, but their hw is still bit limited.

OPNSense is quite nice and easy free and open source firewall/router solution.

If you want to add bit of flexibility, you can use some virtualization platform like VMware in to the machine, so that you can run OPNSense in it, with some other virtual servers.

Then when you get things working, you can start looking in to VLAN's, because they are quite important part of enterprise networking. Most cheap switches nowadays support VLAN's out of the box.

A custom router + managed switch is a great way to learn. Studying the fundamentals is also good, but in my opinion it's not as fun as setting up your own network and learning hands-on.

If you decide to go this route I highly reccomend taking regular backups of your config (and backup again before you change stuff). Part of learning involves breaking things - trust me you will break your network - and in networking that's one of the best ways to learn. Backups will give you an easy way to restore to a known working configuration.

I started learning networking with OpenBSD's tutorial on building a router.

Building a router forces one to learn networking.

https://www.openbsd.org/faq/pf/example1.html

I don't think you really need to dive that deep into networking to start self hosting, but Network Chuck has a pretty good CCNA course on YouTube https://youtube.com/playlist?list=PLIhvC56v63IJVXv0GJcl9vO5Z6znCVb1P&si=VOajj1fJjb-Sx58p

If you want to learn to secure your network, try using snort. It’s a popular intrusion preventing system.

Another interesting thing is to host a Wireguard VPN server. You can access your selfhosted services from outside of your house by connecting to the VPN.

In my opinion, learning to setup these kind of things is the most interesting and beneficial way to learn things around them.

I recommend an Orange pi 5 with Armbian installed. Raspberry pi is under powered and it’s a pain getting compatible software for the arch.

You already have a pihole. I assume you like it. You could buy a cheap minipc/NUC and set up proxmox on it and learn to set up and configure a second pihole as a virtual machine. Then you'll have a server running with the ability to expand as needed. You could look into setting up new network gear (like tp-link's omada) and run the software controller in a VM. Or you could dabble with HomeAssistant and get into smarthome. Or set up a photo management tool like Immich. Like others have said, find a problem you want to solve and use these tools!

For project ideas, I think most of us start with a problem and learn how to solve it. But without some foundational knowledge, you may struggle to even realize what’s a solvable problem.

You should maybe start with something like Linus Tech Tips “techquickie” content. Look at tutorials for home servers and home labs.

Or just spin around with your eyes closed, and point at a random tech object in your home, then start searching for info on how that works. How you can customize it, fix it, break it, make your own.

Not sure how else to help you jumpstart what many of us have just been naturally doing our whole lives. Like… be curious. That’s the key actually. Curiosity.

Networking will take you from being "they guy that fixes computers" to full blown Telco engineer. It's a lot though, more than I can explain. Get managed switch and start having LAN parties.

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

6 acronyms in this thread; the most compressed thread commented on today has 5 acronyms.

[Thread #400 for this sub, first seen 4th Jan 2024, 05:55] [FAQ] [Full list] [Contact] [Source code]

I learned most of what I know though network my services and locking them down.

Cisco do free networking courses which teach the fundamentals. The one I did was more theoretical than practical but it really helped me think of what Im really trying to achieve and learning the terminology was really helpful, especially later when trying to troubleshoot and finding help online that was a struggle before the course.

There are assessments as you progress and a certificate at the end.

They also have virtual software you can play around with for different potential configurations. Thats much cheaper than buying lots of hardware!

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