MC-97523Nether Portals briefly teleport players to original location in alternate dimension
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is fire or lava at that location then the player takes fire damage after portal invulnerability has ended. This is accompanied by massive server lag / desync in MP and massive frame lag in SP. This is most likely caused by the anti-cheat (speed hacking) engine teleporting the player back to the original location.
e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Overworld ==> Nether:
Fire damage (after portal invulnerability has ended)
Note:
In 1.9 pre-4 this issue was partly fixed by the adding of portal invulnerability. However this workaround is temporary for the 1.9 releaseat best as you still load the far-away chunks, catch fire and so on. The real underlying issue is the anti-speed hacking engine or whatever it is that produces those <PLAYER> moved too quickly messages being too trigger-happy.
Linked Issues
is duplicated by1
Created Issue:
Nether Portals briefly teleport players to original location in alternate dimension
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the players to their original (starting) location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://www.youtu.be/r820JNf6rk8
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the players to their original (starting) location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://www.youtu.be/r820JNf6rk8[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the players to their original (starting) location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
youtu.be/r820JNf6rk8
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the players to their original (starting) location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
youtu.be/r820JNf6rk8[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the players to their original (starting) location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://www.youtu.be/r820JNf6rk8
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the players to their original (starting) location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://www.youtu.be/r820JNf6rk8
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the players to their original (starting) location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)Lavaat (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)Stoneat (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can dieif there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://youtu.be/r820JNf6rk8[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://youtu.be/r820JNf6rk8
relates to
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
In SP it ispossible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://youtu.be/r820JNf6rk8[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
It is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a; still works like this in pre-2):
https://youtu.be/r820JNf6rk8
![[Mojang] Grum (Erik Broes)](../../../data/assets/gravatar/grum.png){kind=small}
[Mojang] Grum (Erik Broes)[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
It is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a
; still works like this in pre-2):
https://youtu.be/r820JNf6rk8[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
It is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (06a):
https://youtu.be/r820JNf6rk8
Video (pre-2):
https://youtu.be/5yhF9-tWCPc
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
It is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (
06a):
https://youtu.be/r820JNf6rk8
Video (pre-2):
https://youtu.be/5yhF9-tWCPc[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage. The player is actually at that location, server-side, even after pre-2. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
It is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (pre-2):
https://youtu.be/oRu6rf4xNt8
[Re-report of MC-89928 issue 2 as requested]
Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is a wall or lava at that location then the player takes at least one tick of suffocation/fire/lava contact damage.The player isactuallyat that location, server-side, even after pre-2. This is accompanied by massive server lag / desync in MP and massive frame lag in SP.e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in nether
Corresponding nether portal at (12,64,12)
Stone at (12, 64, 12) in overworldOverworld ==> Nether:
Contact lava/fire damage
Nether ==> Overworld:
Suffocation damageNote:
It is possible to take more then one tick's worth of damage so you can die if there is lava at the alternate dimension.Video (pre-2):
https://youtu.be/oRu6rf4xNt8Nether Portals briefly teleport the player to their starting location, but in the other dimension. If there is fire or lava at that location then the player takes fire damage after portal invulnerability has ended. This is accompanied by massive server lag / desync in MP and massive frame lag in SP. This is most likely caused by the anti-cheat (speed hacking) engine teleporting the player back to the original location.
e.g.
Overworld portal at (100,64,100)
Lava at (100, 64, 100) in netherOverworld ==> Nether:
Fire damage (after portal invulnerability has ended)Note:
In 1.9 pre-4 this issue was partly fixed by the adding of portal invulnerability. However this workaround is temporary for the 1.9 releaseat best as you still load the far-away chunks, catch fire and so on. The real underlying issue is the anti-speed hacking engine or whatever it is that produces those <PLAYER> moved too quickly messages being too trigger-happy.
relates to
duplicates
relates to
is duplicated by
Done
MC-97523
(sorry if I'm too late)
Maybe link this issue above to help direct people with more information?
The way I understand, there are/were three issues:
- Bug 1: Players end up at their original coordinates after using portals, coordinates do not correct themselves. This is what
MC-89928was for originally. This is fixed now. - Bug 2: Players take damage after using portals because they come out at their original coordinates for a very short time before the coordinates update for the new dimension. This was originally thought to be part of bug 1 and as such was part of
MC-89928. Bug 1, after a few attemps, has been fixed in 1.9-pre2, but bug 2 persists, as pointed out by ProfMobius in the comments ofMC-89928.MC-97523was created for bug 2. I consulted with grum on how to proceed, he said bug 2 was actually fixed. As such,MC-97523was resolved as fixed for 1.9-pre2. He said the issue people where people took some damage when using portals in 1.9-pre2 is a separate bug, bug 3 (see below). After proof was provided thatMC-97523is in fact still happening in 1.9-pre2,MC-97523was reopened. - Bug 3: Players take damage when using portals, this damage is not caused by lava/fire/solid blocks at the overworld coordinates in the nether. Per grum's request this is tracked in
MC-89928. I don't understand this issue entirely so I haven't been able to update the description forMC-89928.
I hope this clears things up, I'm sorry we haven't communicated this properly so far.
The bug
The anti-cheat engine is being over-zealous causing the following issues with nether portals, caused by the game teleporting a player back:
- Portals setting the player on fire if there is lava at the exact location of the entry portal in the other dimension.
MC-97523- Can kill player if they are low on food or health - very serious.
- Deals 11 damage (5 1/2 hearts) over time.
- Usually survivable in survival mode, especially if you are full on food or have good armour - you will only take 1 or 2 hearts' damage.
- Portals loading chunks at the exact location of the entry portal, but in the other dimension.
MC-97523- Only the chunk at the exact location of the other dimension's portal loads.
- Only the terrain is generated: entities do not spawn.
- InhabitedTime of that chunk is 0.
These issues are usually characterised by a debug message in the chat claiming that the player moved too quickly:
[11:07:36] [Server thread/WARN]: FM22 moved too quickly! 8740.213380243677,-16.0,8751.561382695907
(this was going through a nether portal in the overworld at 10 000, 10 000).
Workaround
Remove all fire/lava at the exact location of the entry portal in the other dimension. E.g., if you have a portal at (100, 64, 100) in the overworld and you are set on fire when going to the nether, go to (100, 64, 100) in the nether (not to the location of the exit portal) and remove fire and lava around that exact location.
Related issues
MC-90062 - which covers the other effects of the cheat engine changes
MC-86850 - which covers how taking certain actions may cause you to remain at the erroneous location.
The fix
A suggested fix by Xcom6000, Timothy Miller, and [Mod] Pokechu22 can be found in this comment.
I will make a video showing all the issues soon but MC-97523 has a couple videos showing portal behaviour (although you now take less fire damage in pre-4). I tested all these issues which were claimed by other people on a fresh world on a 1.9 pre-4 server, if you would like to reproduce them.
The "other" coordinates in the Nether could potentially be very far from the actual exit portal - if you went from an Overworld portal at 800,y,800, it would briefly put you at 800,y,800 in the Nether (which could contain fire or lava) before teleporting you to the portal closest to 100,y,100.
Taking more than one tick's worth of damage is also possible in multiplayer, please update the description accordingly.
As an unrelated note, I'm not sure this has anything to do with the position bug
MC-89928, as portals with lava lakes at the corresponding coordinates no longer set players on fire in 1.9-pre2.@Fenhl this may be due to some type of fire resistance or invulnerability. It makes no sense that you take a tick of suffocation but not lava damage unless this was the case...
I've noticed that my admin noted that most of the "moving too fast" errors had disappeared from the console in the most recent Pre-Release versions, EXCEPT for when people were traveling through the portals... My question: is this, like suggested on other bugs close to this (
MC-89928,MC-90605and maybe others), could this be an issue with the server saying "you moved too fast from coordinate "x" to "x/8" (or conversely from x to x*8) and temporarily teleporting you back? I'm half wondering if half of these bugs that have been 'patched and closed' are actually useless code that have acted as bandaids for an over-active anti-cheat measure? Sorry if the logic in my mind is not making sense, but if all of these fixes since 15w42a have been fixing the end result of the bugs instead of what's causing them, won't the remaining cause still be the same and cause overall instability in the system, let alone server resources (loading unneeded chunks, network traffic, etc)?I'll give a reason my mind says
MC-90605was happening that relates to this bug: You teleport to the dimension, anticheat tries to put you back, something added in 15w42+ puts you back in the portal, next thing you know you're being transferred back to the previous dimension because you entered and then left the portal then came back (all by the servers doing), and you get looped back because the cooldown on the nether portal looping is now broken by you entering and leaving then reentering (read above, but the servers doing). Now it was fixed in 16w06 by adding a cooldown. — AGAIN, this is fixing the result, not what caused the result.My message to Mobius... look into, at least for a second, the root of the issues. Which I believe at this point the anti-cheat measure saying you moved too fast. Then you could probably remove all of the added bloat of correcting a bug that has cascaded into everything from changing dimensions to portal looping by breaking preexisting mechanics that were designed to prevent this in previous versions of the game.
@Fenhl in my testing I /setblocked lava at that location and promptly died when I went through.
Grum, this is fixed as 1.9-pre2. Did you mean Future Version 1.9?
[Mojang] Grum (Erik Broes) this is definitely present in 1.9 pre-2
Changed fix version.
Actually this is fixed... unless someone can show a video of themselves using a portal and taking lava/fire damage when the overworld coordinates in the nether are filled with lava, and then taking suffocation damage when they are filled with solid blocks, in 1.9-pre2 (F3 screen).
I can't prove that it has anything to do with coordinates, but I can absolutely confirm that I still take a tick of damage going through nether portals in -pre2. Whether it's suffocation or something else I have no idea. I don't know how to capture a video but I'll try to get some screenshots.
I think Grum wants us to use
MC-89928I'll post these screenshots on the other bug as well but as you can see from the filenames, they were taken in quick succession. Based on this evidence I actually don't think this bug has anything to do with coordinates any more, because the nether screenshots have the correct nether coordinates immediately. But as you can see, I still take damage while waiting for the chunk to load.
I will make another video then
Single tick of damage is
MC-89928. If your coordinates are still messed up we can reopen this ticket.OK, close this, I misunderstood what you were saying.
@redstonehelper The single tick of damage is caused SOLELY by this bug. It's caused by the game teleporting you to the wrong coordinates (which would be this bug), which happen to be in solid blocks (or catches you on fire if it's lava). This is still going on in even Pre-2. Why are we opening new tickets for the results of a bug? If this bug was fixed all of the damage on teleport bugs would simply cease being a thing, and to be honest, I think it's leading the Devs down the wrong path.
@James Koon thus bug was opened solely due to redsotnehelper's request to split the issues up; Grum has since reopened the other one which is much more visible.
To add to that, the single tick of damage is not due to player coordinates updating too late. There is another cause.
@Redstonehelper That is completely false; see James Koon's video.
Reopened once more after seeing the last video in the description.
With all due respect, this reopening and closing is very confusing. What reports correspond to which issues?
The way I understand, there are/were three issues:
MC-89928was for originally. This is fixed now.MC-89928. Bug 1, after a few attemps, has been fixed in 1.9-pre2, but bug 2 persists, as pointed out by ProfMobius in the comments ofMC-89928.MC-97523was created for bug 2. I consulted with grum on how to proceed, he said bug 2 was actually fixed. As such,MC-97523was resolved as fixed for 1.9-pre2. He said the issue people where people took some damage when using portals in 1.9-pre2 is a separate bug, bug 3 (see below). After proof was provided thatMC-97523is in fact still happening in 1.9-pre2,MC-97523was reopened.MC-89928. I don't understand this issue entirely so I haven't been able to update the description forMC-89928.I hope this clears things up, I'm sorry we haven't communicated this properly so far.
OK I will test these bugs later and confirm fixes if possible. Thanks for clearing up!
I'm not sure if and how this is connected but this is my experience, after upgraded to latest snapshot (pre-2):
Bug 4:
It takes about a minute to unload the world, before the "Downloading terrain" message appears and loads the other dimension. I have noticed, that during that time my hard disk is used 100%, which is SSD of type M.2 (really fast).
(Unloading - the time when your screen goes to Netherrack texture when using portal, but hasn't displayed the "downloading terrain" message yet.)
For test purposes, I have reduced the render distance, down to 2 and all went well in any direction (Nether<=>Overworld).
After player is killed, all items are lost (***), instead of dropped on the ground.
==================================================================
Here, at some point of writing this, I have noticed, that I have Java update notification.
After updating to 1.8.0-73_64bit, I have managed to use the nether portal as intended (even with Render distance 32). (No idea if it's related or not, but unloading time has reduced to "non-existing".)
Then I was rubber-banded back to portal, with all my items back.
I guess, that the game takes at least 1-tick to load your items, after using portal (load the dimension). I have a few automated redstone contraptions, with loads of mobs (400+), that sometimes make the game ticks run slower when loading.
My point is, that if the player is insta-killed, before the dimension loads, there are no items to be dropped, since they weren't loaded yet.
This video was originally made for
MC-89928, but it offers a side by side shot of what's happening in Pre2, if you would like to add it to the description.https://youtu.be/n9hZgJDO9TA
https://youtu.be/oRu6rf4xNt8
More proof the player is actually there, server side. I think this one is quite useful as it shows that the player actually dies at that location.
Please resolve this as duplicate of either
MC-89928orMC-98153I have watched James Koon's videos and did some of my own testing, and did some reading over the MCP 9.31 code. Since entire teleportation and changing dimension code is only executed server side, and client is not informed about changing of the coordinates, it might be the case, that the player enters the other dimension at a correct location (A), then client updates player position to (8*A or A/8), clients last known location (for one tick), then server decides to move the player back ('Player moved wrongly' message). It might be just client server dissynchronization issue. It is visible on James Koon's videos, that from the other account perspective (thus not linked with the client of the first account) other account lands on the portal, then moves via clients request to the old coords and then is moved back by the server the third time.
Glad someone actually looked into this... hopefully someone at Mojang can fix this, I'm tired of policing nether portals on my server.
Yep - happend to Xisuma on his stream. crashed the game while going thrgouh the portal and the server were not able to correct his position ('moved wrongly' massage) and end up in the exact coords of the overworld, but in the nether.
https://www.youtube.com/watch?v=-Y6ygA6NiNI