NoCheatPlus
Detect and fight the exploitation of various flaws/bugs in Minecraft!
Introduction
NoCheatPlus attempts to prevent cheat clients from exploiting weaknesses of Minecraft or its protocol, making your server more safe. Checks cover a wide range of issues including flying and speeding, fighting hacks, fast block breaking and nukers, inventory hacks, chat spam and other types of malicious behaviour. For a more complete list have a look at the Features Page.
NoCheatPlus puts emphasis on configurability and allows you to customize actions that are carried out when a player fails a check (e.g. silent cancelling, executing commands, just logging). Bypass permissions allow to control what check to apply for which players, all checks can be deactivated in the configuration, also having the option for world-specific configuration files. Many checks allow more detailed configuration to adjust sensitivity.
Certainly NoCheatPlus is not a magical bullet, it uses a lot of heuristics and even guessing, so you will encounter false positives here and there and also not catch every single violation. Example video of how NoCheatPlus blocks cheats (outdated plugin version).
NoCheatPlus was introduced by NeatMonster, building on the code base of NoCheat by Evenprime.
Recommended
The following plugins might be useful to have a look at.
ProtocolLib
Allows NoCheatPlus to activate packet-level checks, covering a range of exploits that can't be monitored using ordinary means. Since roughly Minecraft 1.7.10, the fight.speed check can't work as expected anymore, due to changes in CraftBukkit. With ProtocolLib this can be repaired.
CompatNoCheatPlus (cncp)
Make plugins like mcMMO or MachinaCraft more compatbile with NoCheatPlus. Not all existing plugins are covered (yet), but you can leave a note or create an issue/ticket request for cncp. Phasing out: Citizens 2 should work with NCP out of the box, MagicSpells are working on compatibility too - rest will be integrated into NCP.
Orebfuscator
Orebfuscator fights all sorts of X-ray-hacks by altering the map information that is sent to the players, such that they have to mine blocks to actually reveal what is behind. Virtually a "must have". (Latest versions of Spigot contain features of Orebfuscator.)
Downloads and History of Changes
- Download officially approved versions on the Files page at BukkitDev.
- Development builds have been moved over to the Jenkins at md-5.net.
- Do not download from any other source, do not use jars other people send you.
- Change lists: Wiki (digest) | Jenkins (by build number) | GitHub (all commits).
- Source code
Plugin statistics are no longer reported to mcstats.org.
Support
Documentation Resources
- Consider first: Frequently asked Questions and Known Issues.
- Wiki (Configuration, Permissions, Commands)
- Developers might have a look at the page describing the API of NoCheatPlus.
Contact us
- Quick questions can be asked on this page,
or on IRC (Server: irc.spi.gt | Default-Port: 6667 | SSL-Port: 6697 | Channel: #nocheat | Web client: WebIRC) - For real issues or feature requests please create a new issue/ticket or add to an existing issue/ticket.
- To send information that is not to be seen by all, you can also reach us by PM to @asofold and @MyPictures. @IceAP (IRC: ICE) will also help or redirect the conversation. Please do not contact the user 'NoCheatPlus', it is for administrative purposes only and will likely not be answered in time. Keep to BukkitDev and GitHub for support, do not trust users on other forums or websites, also not if their nick names are the same as NCP staff on BukkitDev.
Please always state the output of the "ncp version" command to let us know versions in use (users of cncp also the "cncp" command).
Comments
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_ForgeUser9668734 Owner
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_ForgeUser15078623 Ticket Manager
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_ForgeUser16101223 Contributor
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_ForgeUser7091862 Former Author
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_ForgeUser7459264 Former Author
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Forge_User_61842651 Author
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MyPicturesCP Artist
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Posted Nov 11, 2012@asofold
Already using build 3.8.0 The issue with NoCheatPlus is that it assumes the server is running 20TPS and never has lag spikes. The second a lag spike happens the plugin thinks the world is ending by how much spam we get. Every three seconds we get messages like "Name meets the improbable more then expected" when they are simply building there home.
We get false fastbreak notifications all the time. Oh "name tried to do "blank" with too high a frequency" happens a lot aswell.
The thing is. with us and most servers, our TPS dips to 14/17 sometimes, We have nearly a hundred players online, we get lag spikes once in a while.
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Posted Nov 10, 2012@mrchasez
I think it is an issue with CB/MC rather, because the check is pretty accurate and harmless.
Please update NCP as well. False positives are very unlikely with relog, what might have happened is a severe server problem disconnecting the players without assuming them disconnected, on relog they will instantly logout and login (from the perspective of the server), so ncp prevents that. It is more likely to be a server crash problem (see pm).
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Posted Nov 10, 2012@asofold
So many false positives all the time. So much spam ಥ_ಥ
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Posted Nov 10, 2012@mrchasez
The fast relog check only checks if players log in too quickly after logging out (chat.relog). So if after logout/connection loss they log bacl in right away NCP might prevent it, the check can be deactivated without too much trouble, but i doubt it is your problem.
The end of stream should not have anything to do with NCP, can you send me a log (pm) which shows what happens before end of stream occurs?
You should probably use build 236, though.
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Posted Nov 10, 2012Major issue! On build #223 and any after #218 The server randomly starts kicking players. http://pastie.org/5358772
Thats not the bad part, Once they try to log back it. It stops them!!
[INFO] Disconnecting Andilitox [/190.4.65.169:49775]: Too fast re-login, try with a little
It does that for everyone. How do i fix this? So then no one can join for many many hours until i come back and manually restart the server, then after an hour or two it does it again!
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Posted Nov 9, 2012@lst96
Is that the default message of the recent builds ? I though they have "... you're ..." .
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Posted Nov 9, 2012not really problem but in config at You relogged really fast! If you keep doing that, you''re going to be banned. there extra '
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Posted Nov 9, 2012@rasnyderiii
Please try 235 then.
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Posted Nov 9, 20123.8.1-b231 keeps saying my config is out of date even though I delete the config and have let it regen.
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Posted Nov 9, 2012@CBGaming
Yes there is, did you check out the configuration link above ? You do like "cancel vl>50 log:..." to silently cancel until vl 50 then log.
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Posted Nov 9, 2012is there a way to change what the violation level needs to be to show up in chat? I get spammed with level 1 violations all the time and most of the time it's just lag.
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Posted Nov 9, 2012@asofold
Sadly yes, I'm sending a message to the author about this issue. It's only wood stairs, (how?) so I just removed the function from them for now.
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Posted Nov 9, 2012@Puremin0rez
I doubt it has to do with NCP in a direct way. We are not doing anything with overriding protocol internals, so that is all up to CraftBukkit and other plugins, or even Minecraft itself. If the client can't handle effects of events being cancelled then it would be a CraftBukkit or Minecraft issue, rather.
@Log actions
I am currently reviewing parts of the actions handling, such that it won't be necessary to remove actions that never will be executed due to global flags overriding them (log actions for instance).
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Posted Nov 9, 2012@MasterGabeMOD
Man I've been getting that issue alot too, people will just become desynced from the server and stay in one place while they're really running around doing things, then fall out of the world or relog and find out they've been rolled back because they never really "moved" on the server..
Is this related to NCP? Or is this some sort of bukkit / mc issue?
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Posted Nov 8, 2012@andrewkm
The total times only say that NCP does a lot of stuff. It can be totally ok if NCP uses ten times more than your previously heaviest plugin :) - Question is if there are extreme spikes due to NCP or if the average processing is just too much. Also the judgement should depend on what plugin you are comparing to. Would be interesting to see individual events timings, if possible in comparison to another big plugin like WorldGuard or Essentials on the same machine.
To increase performance one might not only disable some logging globally (decide for either file or console, possibly reduce ingame logging), but also remove disabled entries completely (a log:x:1:2:f entry with deactivated file logging might still get called internally, though it does nothing, this is subject to improvements in the future too). Then you can work with kicking for some checks (we are lacking a list describing which check is influenced by lag, false positives most) and also "/ncp tempkick" to kick people for a little longer depending on what they were doing.
@MasterGabeMOD
There might still be fly bypasses, though. The moving checks are somewhat complicated and also can't be done too simplistic, otherwise bypasses will be even easier. Basically lots of the modeling is the old one (not sure it ranges back to EvenPrime, at least since NeatMonster was active last time), i am slowly working into it, trying to understand and improve all details until i know which parts are really necessary to keep, model-wise. I will not try to re-implement the whole thing right now, but i am experimenting with complementing it by some accounting methods (currently those do depend on sorts of lag a little, so until proven that they help against some bypasses, you might disable accounting, the coming versions will sharpen flying checks though.).
@Liger_XT5
Comfort? So that is another plugin?
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Posted Nov 8, 2012@asofold
Nothing shows in log other than attempting to survival fly.
After coming back from work, I was told this happens with the comfort plugin and on wood stairs. When someone attempts to sit, they are somehow put into fly mode. Further attempts to jump or fall causes the issues. I will remove the wood stairs from the comfort list.
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Posted Nov 8, 2012@MasterGabeMOD
I've been disabling logging since months :P My config is pretty much default completely except exactly what your screenshot shows :)
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Posted Nov 8, 2012@asofold
This fly issue is due to some glitch that's not sending the avatar's location. Basically, sometimes after a while the server stops receiving the players location. So for example, when a players stops for about 5 minutes, walk away, then logout, they're back in that location that they were just in when not moving for 5 minutes.
I don't think this is NoCheatPlus issue, as I'm not running NoCheatPlus on my big server at the moment. I'm finding myself multiple times building something, logging out, then it will be gone. This could most likely be a Bukkit or Minecraft issue.
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Posted Nov 8, 2012@andrewkm
I would recommend disable logging. Just make it look like this: http://i.imgur.com/AYizT.png If that doesn't help, try experimenting with the checks to fit your needs.
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Posted Nov 8, 2012@andrewkm
BTW are there any checks you recommend disabling which may not be needed in your opinion to help improve performance?