TryHackMe Networking
TryHackMe is a company that provides high-quality security training, and some really good stuff is free.
As another free fundamentals training site, Roppers and THM are natural enemies and I hate them with the heat of 1000 suns. With that said, I think they teach stuff in an interesting way and I like the way they do things.
Your first networking challenge is figuring out how to use OpenVPN to connect to their networks:
https://tryhackme.com/access?o=vpn
Verify successful connection with this: https://tryhackme.com/room/tutorial
Work through these three sections from them
- What is Networking? - Begin learning the fundamentals of computer networking in this bite-sized and interactive module
- Introduction to Networking - An introduction to networking theory and basic networking tools
- Introduction to LAN - Learn about some of the technologies and designs that power private networks