What are /r/DoesAnyoneKnow's favorite Products & Services?

From 3.5 billion Reddit comments

Among the other things mentioned - Is the port active? Is it plugged into a switch/router/modem somewhere else in the building?

These ethernet testers are cheap enough and can tell you if you have a bad cable and if you're getting signal all the way back to your modem.

https://www.amazon.com/Optimal-Shop-Network-Tester-Ethernet/dp/B072LJYHKP/

To use it, pull the ethernet cable from the computer and plug it into one side of the tester. Pull the cable coming from the wall out of the modem or router and plug it into the other side of the tester leaving the cable plugged into the wall. Check both sides of the tester to make sure it counts up to 8 in order. The fat side should have a switch that when turned on will begin the counting. The skinnier side will receive the signals and count up along with it. If the skinnier side doesn't light up at all then your ports aren't wired through. If it counts up out of order or skips numbers then you have a bad cable.

Late to the game here, but other copies may be available cheaper, if you're interested.