This is a great video that demonstrates things mostly using the cisco router configuration command line (at least that’s where I’m familiar with these commands from). He sets up two example networks to demonstrate DNS and then peers them together to demonstrate BGP. If you ever studied for CCNA or similar, you learn some of this material.
Ben Eater explains things excellently as always. Both the DNS and the routing segment are (if somewhat high level) good explanations on how these systems work in the real world and how we interact with them.