Ask HN: What are the best resources for learning networking?
What have you found to be the most helpful resources to learn about things like network interfaces, VPN's, NAT traversal, hole punching, DHCP, etc.?
In the mean time download Packet Tracer. It’s Cisco’s educational simulator for routers and switches. You can interconnect devices and also connect into the devices to configure them.
If you just use wireguard then you have free reign to make any topology you want. And then you get to troubleshoot the routing mess you've made.
For me, it's been decades since I first grokked what a subnet mask is.
Also reading TCP and IP RFCs will greatly help you.
Read the first 500 pages until you get to the physical layer. Skim the back half of the book on funky protocols like Bluetooth, satellite and cell phones.