https://d.tube/#!/v/ds-tech/iorb7er4n7b
A crash course to computer networking, particularly with Linux, but most of what I show you here applies to Mac/Windows as well.
We go over basics such as:
Routers, Switches, and NICs
Gathering your network's information
Port forwarding basics
Networking tools like nmap, netstat, tcptrack, etherape.