Ever played on a multiplayer server, built near other players and when returning from the Nether, surprisingly found yourself in another player's base? It's because of the 8:1 block ratio between the Nether and the Overworld. It's really weird though that you enter a portal in the overworld, and then when going back through where you came. come out of a different portal in the overworld. This mod fixes that issue.
It keeps track of what portals a player went through in order to ensure correct destinations when the player is going back through the same portals. This is honestly kind of hard to explain in text, even though it's a super simple concept. Here's a comparison image instead:
This mod only needs to be installed on the server (but it works in singleplayer as well).
If you are using SpongeForge, make sure to use the latest version of both this mod and Sponge! It should be compatible now.