Alright, so following the many guides on how to create your own MC server I have one, but anyone not on my computer is experiencing intense lag. I know it's not hardware as I have no lag while hosting and playing in the server, so if anyone has any tips on how to reduce lag, I'd greatly appreciate it!
So, I'm basically having the same issue, but it's not home-hosted. I'd stop any redstone-clocks and/or remove plugins. A software upgrade with your router would work as well. It also could be the server's networking card that needs improvement.