Why does my Nether portal connect to someone else's?
Every time you travel through a portal, the game searches for the "closest" portal in the other world to go to. That explains why your portal can end up going to someone else's area in the future: because that other person's portal is now closer than your original one.
Why does this happen?
- Every step you step in the Nether is equivalent to 8 steps in the overworld, so everything in Nether is essentially closer together, which means two Nether portals for far away bases may actually be really close together in the Nether.
- When you first travel through a Nether portal, the game makes a new portal in the other world if it can't find an existing one, but it creates this new portal in a random location within some radius.
To fix it, you want the portal on the other side to be as close as possible to the "ideal location." The formula for the ideal location is simple:
- Take your X, Y, and Z coordinates in the current world.
- If you are going to the Nether, divide your X, and Z coordinates by 8 (keep the Y the same). If you're going to the overworld from the Nether, multiply by 8. These new coordinates are your other-side coordinates.
- Go through the portal and create a new portal as close as possible to those other-side coordinates that you calculated.
To help you with the calculations, you can use the /nethercoords command in-game.