Minecraft Forums

While playing minecraft with my roommate, she noticed that her nether portals are not linking properly. She created one down in the Overworld, and teleported to the nether. On return, it made a different portal. This has happened half a dozen times now.

Is this a bug, or just a glitch?

She just updated 1.4.4 today, and is not modded at all.

How far away was this other portal? Did the new portal appear in the overworld?

New Portal appeared in the overworld, and the first of the portals that appeared was well away from it. All the rest that have spawned have been withing a 16 chunk distance from that first portal, but except that first one, all have spawned on the world's 'ocean level' in the open air almost 50 higher than that first one.

And the portals are sending her to the proper realm, ie from Overworld to Nether, Nether to Overworld. But not to the portal that existed - it spawns a new one.

That is not unexpected. You should read the portal pages on the wiki in order to understand how portals really work.

Im having some problems too. My first portal is at z -95 my second is z-1180 dont they only have to be 1025 blocks apart

No.

Normal World portals that are within 1024 distance of each other on both X and Z axis are almost always going to link to the same Nether realm portal on initial construction because 1024 translates to a distance of 128 in the Nether Realm, and the game checks for existing Portals within 128 "radius" around the destination (the 257x257x128 box).

Note the "almost always". Note also that it doesn't say that the converse is true. In fact, this diagram shows that you can have Overworld portals that are ~2048 link to the same nether portal.

Imagine you use McEdit to create a Nether that is solid netherrack for thousands and thousands of block. Make one cave with a portal somewhere in there. Almost any Overworld portal will now go to that one single cave, since it is the only possible place for a portal to be. On the flip side, that portal will likely take you to only one of the possible Overworld portals.

The explanation makes sense (I have looked over the wiki in the past regarding how portals work). But the biggest issue is that it creates a brand spanking new portal when you go back to the overworld. annoying as hell too!

It must be a bug in the portal spawning system. If you report it on the bug tracker, they might be able to fix it in the next snapshot or the next future update.

And yet, for some people, you can use blue wool to mark every portal from your home to the portal. If it spawns a new portal, try the first portal.

It is not a bug. It's normal portal behavior and how they have always worked.

If you provide the X&Z coords for the portals we can determine whether minecraft may possibly is at fault, however gerbil is most likely correct. You probably just jumped to the conclusion that the new update was the cause.

Okay, here goes. I am going to notate portals as (x,y,z), where there are two numbers denotes where the two bottom most obsidian bricks are located. I have emulated the issue in her world, yet again, and noticed another weird facet - the facings do not always stay constant either.

The first portal set, in the Overworld, was at (-1879/-1880,10,804). This leads to Portal 2
Portal 2 (Nether) -218/-219,49,94

Now on leaving the Nether, it lead her to a few different portals, I have listen three portals here - the first portal is still active this entire time. These next three portals are in the Overworld.

Portal 3 -1753,63,763/764
Portal 4 - -1756/-1755,63,759
Portal 5 - -1752/-1753, 63, 762

Quote from ckstonge

Okay, here goes. I am going to notate portals as (x,y,z), where there are two numbers denotes where the two bottom most obsidian bricks are located. I have emulated the issue in her world, yet again, and noticed another weird facet - the facings do not always stay constant either.

The first portal set, in the Overworld, was at (-1879/-1880,10,804). This leads to Portal 2
Portal 2 (Nether) -218/-219,49,94

Now on leaving the Nether, it lead her to a few different portals, I have listen three portals here - the first portal is still active this entire time. These next three portals are in the Overworld.

Portal 3 -1753,63,763/764
Portal 4 - -1756/-1755,63,759
Portal 5 - -1752/-1753, 63, 762

The facing changing is a new occurrence in the 1.4 build. Still not sure if it is an intended change or a bug, but hoping the latter.

Regarding the portal issue, I can see very quickly it is because the Nether portal had to be relocated when it was generated, likely due to an obstruction of netherrack or a large lava pool. In this case it was relocated far enough that it can't link up to the first overworld portal when you return. You can verify this by multiplying the -219 X coordinate by 8. This equals -1752 which is the same general area all the other portals are being generated. This happens sometimes. Your solution is to rebuild the portal in the nether at coordinates X= -235 Z= 100 or at least a little closer that way (as long as you remove the other portals)....it's just barely outside the portal search range now.

Thanks - i am just burned out on number crunching myself, and had not looked at things - however having it spawn in new portals was new - two of the portals at y: 63 were operating at the same time - i thought that things like that didnt happen due to the portal going to nearest portal first, then make another?

Quote from ckstonge

Thanks - i am just burned out on number crunching myself, and had not looked at things - however having it spawn in new portals was new - two of the portals at y: 63 were operating at the same time - i thought that things like that didnt happen due to the portal going to nearest portal first, then make another?

I had assumed you had broken or turned off the others as they happened. Is that not so? Perhaps I'm misunderstanding completely...

Only in one case did we have a portal spawn when there was a portal already 'on' and present. But for some reason it kept spawning portals. All in the same area, at those coordinates. All of the four bottom blocks of obsidian are also still present. So it should have remade the portal on those, if my understanding of portal connectivity is proper.

well.. no it wouldn't. For one thing leaving the four bottom blocks is changing the landscape, which changes the distances.
For another thing, the left and right half of the portal are 8 blocks distance difference in location once translated from the nether to the overworld. This combination can easily result in a scattering of portals being created in the 'target' area.

I know this thread is over a week old, but the portals on one of the SMP servers I play on have been acting strangely since the 1.4.5 update. We've had a network of portals in place and working as expected since we started the world, but today when I went to use the portal in my home it created a new portal instead of taking me to the one it usually does (I'm close enough to someone else in the overworld where we share a portal exit in the Nether). I figured "okay, it'll just take me back to my portal when I go through this new one" but instead it generated a brand new portal on top of a tree. I double checked that my friend hadn't moved his portal, and then I checked a few of the other portals on the server. They went to the expected destination portals but upon returning to the overworld a new portal would be generated.

I'm not sure what happened with the update, but there's been very little activity on our server lately and I seriously doubt anyone's made significant enough terrain modifications to mess with the portal linking that's been working just fine for the last year or so.

Quote from macskull

I know this thread is over a week old, but the portals on one of the SMP servers I play on have been acting strangely since the 1.4.5 update. We've had a network of portals in place and working as expected since we started the world, but today when I went to use the portal in my home it created a new portal instead of taking me to the one it usually does (I'm close enough to someone else in the overworld where we share a portal exit in the Nether). I figured "okay, it'll just take me back to my portal when I go through this new one" but instead it generated a brand new portal on top of a tree. I double checked that my friend hadn't moved his portal, and then I checked a few of the other portals on the server. They went to the expected destination portals but upon returning to the overworld a new portal would be generated.

I'm not sure what happened with the update, but there's been very little activity on our server lately and I seriously doubt anyone's made significant enough terrain modifications to mess with the portal linking that's been working just fine for the last year or so.

Yeah they messed around with the portal code. Your facing no longer stays the same and there does seem to be some odd occurrences like you describe with old portals not working like they used to.