Is it possible to change the linkage of Nether portals?

Nether portal have a special algorithm to link.

When you cross a portal in the overworld, it computes the nether exit by dividing the coordinates by 8 (X and Z only). Then the game look for the closest already existing portal within 128 block radius around that position. If there is one, you have your exit. If not, a portal is created.

Reversely, when comming from a nether portal, the game multiplies the coordinates by 8 and look for the closest portal within 1024 block radius around the computed coordinates.

So for the long travel idea you would need to do as this:

• Write OW coordinates. Spawn your portal and go to the nether.
• You should create a new portal (first one). Mark the location and check it is around the coordinates of your first OW portal divided by 8.
• Destruct this portal and build it as far as you can from its original location in the direction of travel, that is to say at the edge of the 128 block radius.
• Write the N coordinates and compute the equivalent OW coordinates

In this configuration, the first portal A links to B and B to A by the means of the "closest active portal" rule.

• Add a portal in the OW in the direction of travel that is closest to the last OW coordinates you have written.

You have now the new portal C linked to B (closest active portal in the nether) B to C (closest active portal in OW) and A to B (closest active portal in the nether). You can fast travel A -> B -> C now.

If you need a longer route:

• compute the nether coordinates equivalent to the C portal.
• Build a D nether portal closer to this point than portal B in the direction of the travel and repeat the operations.

The key here is to exploit the "closest" search algorithm. Do not use original spawned portals cause they are centred in the radius range. Warning, do not build new nether portal after this in the influence zone of your fast travel road. You could easily messed things up.

It depends.

As this page indicates, the (X,Z) coordinates of the portal in the overworld should be approximately 8 times as large as the (X,Z) coordinates of the portal in the nether that you intend to link to.

So if portals are slightly misaligned, you can either build new portals or destroy existing portals in the "correct" locations (as determined by the coordinate system) to change the linkage. However, two portals that correspond correctly will never change destinations to a newly constructed portal unless one of the portals is destroyed.

So here is how I solved it:

• I deleted both 3 and 4

• I placed the player to 5 and entered the portal in-game

• This spawned a new portal (6) in the Nether because there was no portal in range to link to.

I used MCEdit because I think this is a defect in the game, but if you are not lazy like me or want to play without cheating, you can travel in the Nether from 2 and destroy 4, go back via 2, then travel to 3 in the overworld and destroy it there, then travel to 5 and enter (the numbers here correspond to the picture I added in the post).