I know you've asked for books and courses but if you are serious then get practical and self-medicate! You should be able to cobble together some reasonably priced gear. It does not need to be expensive and the more the better. Here are a few ideas:<p>Look out for old Cisco, HPE, Dell or Juniper switches - 10/100Mb ones work fine for learning with. Ideally managed ones with a command line but webby interface ("smart switches") will get you started. If buying new then a Netgear GS108T is a good low price smart switch. There is a lot of documentation for all of these available on the web.<p>Raspberry Pis are pretty cheap and are full Linux boxes with the full firewall/router etc available. The current models have both wifi and wired connections, so you can play with routing. They are powerful enough to run a GUI and a browser which is pretty nifty for £30. If you are not familiar with Linux then these are a good place to start - loads of resources available. Old laptops tend to have both wifi and wired as well and come with a UPS and screen built in, not to mention gobs of RAM and a hard disc! A lightweight Linux distro can make a decent router or a test server or whatever.<p>Consider virtualisation. A decently powerful PC can run a whole lot of mini virtual routers, switches, servers and clients. However, you will need to get to grips with quite a few concepts here as well as networking. Perhaps save it for phase 2.<p>On the internet routers front, investigate the likes of pfSense and open router firmware like Tomato, DD-WRT etc (for my money, pfSense is the man every time).<p>Get yourself signed up for several sub reddits eg r/networking r/sysadmin r/HomeNetworking r/pfsense. Read them and lurk. The Gentoo and Arch Linux forums are worth watching as are the pfsense ones.<p>On the security front, why not grab a copy of Kali Linux - I use it in the day job quite a lot. It can look a bit bewildering at first but there is a lot in there all in one place, already installed. Don't be put off by the silly names for some of the software. For a quick dive in and instant results, on an OS you may be more familiar with, get hold of nmap/zenmap and Wireshark and learn how to use them. Lots of docs for them on the web. Make sure that you search for them carefully and only download from the correct site. As you can imagine there are quite a few <i>ahem</i> unauthorised versions around. Both nmap and wireshark have .org domains and are open source and hence free.<p>Hopefully someone will get you on track with a good book or two and hopefully you'll do the decent thing and fill your home with networking hardware.<p>One last note: networking doesn't happen alone or in isolation - a fact sometimes lost in many orgs with teams for separate functions - "nets", "servers", "apps" and all that stuff. You can't know everything but don't stop at artificial boundaries.