Easy Anti-Cheat sabotages multiplayer on Linux (Steam Play Proton)

Issue Summary:

When playing on Linux through Steam Play Proton, Easy Anti-Cheat prevents others from joining your hosted game or you from joining another host. When attempting to join another game, one is greeted with the error message “You are not allowed to connect. Either this or the other game instance is untrusted by the anti cheat system” (see screenshot).
When hosting a game, no other player can join your game; the chat log gets filled with “Player X is joining the game” and “Player X has left the game” messages (see screenshot).
When finishing a hosted game, one is greeted by an error message stating “Backend rejected the challenge response” and character progression and items are lost.

Steps to Reproduce:

  1. Launch Vermintide 2 on Linux through Steam Play Proton
  2. Join a game OR start a hosted game
  3. Be greeted with an error message when attempting to join OR watch your chat log get spammed with “Player X left the game” messages when hosting.

Reproduction Rate (Choose One):

Constant (100%)

Additional Information:

Steam Play Proton version: Proton 3.16-4 Beta


Hey Itzamna.

The OS requirements for Vermintide 2 are:

OS: 64-bit Windows 7, 64-bit Windows 8 (8.1) or 64-bit Windows 10

Sadly we do not support Linux.

1 Like

Hello Hedge,

I am sorry, but your response is entirely unacceptable. The game itself runs fine on Linux with Steam Play Proton, and Steam Play Proton is an official Valve project. Easy Anti-Cheat is going beyond its mandate as an anti-cheat program and is not kicking Linux users for cheating, it is kicking Linux users for not running Windows. It is fine that Fatshark decides to only support Windows, but you are actively preventing Linux users from fully running your program.

Easy Anti-Cheat appear amenable to a solution, see this Reddit thread: https://www.reddit.com/r/Paladins/comments/606g17/easyanticheat_wine/

In the Easy Anti-Cheat logs on my system, it can be seen that it recognises I am running on Wine and it attempts to download an EAC module for 64-bit Wine (wine64):

[2018.11.19-08.02.04] [Connection] Connecting to URL: https://download-alt.easyanticheat.net/api/v1/games/226/client/wine64/download/?uuid=ec6045bc-61e0-985c-d462-13440608ed07
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] Download Progress: 0%.
[2018.11.19-08.02.04] [Connection] Connect result: SSL connect error (35) Response Code: 0 Destination IP:
[2018.11.19-08.02.05] Connection to the Content Distribution Network failed! Curl Code: 35.
[2018.11.19-08.02.05] [EAC Callback] Code 901. Message: 'Connection to the Content Distribution Network failed! Curl Code: 35.'.

However, no wine64 EAC module for Vermintide 2 is found.

I would like to kindly request Fatshark to contact Easy Anti-Cheat and ask them to make a wine64 EAC module available for Vermintide 2.

Thanks in advance.


Lol, entitled much? If fatshark tries to fix this for you then that opens the door to supporting everyone else trying to run the game on Linux or Mac, which the game is not designed to do.

The game doesn’t support Linux. Take it up with EAC or the creators of the third party tools you’re using.

If you are not a Linux user and have nothing constructive to add, please refrain from doing so. Stay on topic. As an owner of the game, I am by definition and by law entitled to support.

This is not about “supporting Linux”, Windows games (including Vermintide 2) run perfectly on Linux. It is Easy Anti-Cheat that is preventing Linux users from accessing multiplayer, exceeding EAC’s mandate as an anticheat program and instead preventing Vermintide 2 from running on any operating system besides Windows.

Easy Anti-Cheat has made Wine EAC modules available for other games, they can do it for Vermintide 2 if only Fatshark asks them to.

Aren’t you running an operating system not listed in the supported ones? Even if

still, yours is not a supported one right?
In any case, I wish you they can find a solution.
Can you point me some resources where to look for gaming on linux, I stopped like 10 years ago to try anything, but if you can run properly a game like V2, I’m interested again :stuck_out_tongue:

I am a Linux user

Lol is that so? You’re BY LAW entitled to support on an explicitly not-supported operating system?

If it ran perfectly, you wouldn’t have had to make this thread in the first place. How is this not about supporting Linux?

Really don’t know how I could be any more on topic here. You’re literally asking for official developer support on an operating system that they explicitly say in the system requirements that they do NOT support.

I will reiterate: this is not about supporting Linux. Wine supports Windows programs. If not for Easy Anti-Cheat, the game would have run perfectly fine. Aside from multiplayer, the game does run fine - no graphical glitches, no degradation in performance.

The question of what operating system is listed as supported is irrelevant; Steam Play Proton is an official Valve project to allow playing Windows games on Linux through Steam. By using Easy Anti-Cheat, Fatshark are not just not supporting Linux, they are actively blocking Linux users from accessing all features (multiplayer, progression, items). That is way beyond merely not supporting Linux.

Had you really been a Linux user, you would have been far more sympathetic to my modest plea to stop actively blocking Linux users from Vermintide 2 multiplayer. A real Linux user would not be this hostile to making a game playable on Linux.

As it stands, I think you call yourself “Linux user” because you dabbled in Ubuntu once or twice. I dare you to try Vermintide 2 on Linux and report back; until you do, I shall give your arguments no weight at all. Screenshots or it didn’t happen.

Back on topic: Fatshark, have you contacted EAC yet?

1 Like

I dual boot and put my games on the windows partition, like any sensible Linux user who is also a gamer.

But hey, the way you’ve degenerated into slinging insults speaks volumes. Best of luck with your Linux gaming, and as saltz would say: I’m out!

Good for you, but I do not own Windows at all and I do not dual boot. I play games on Linux, like any sensible Linux user who is also a gamer.

You called me ‘entitled’ and ‘insensible’. The pot calls the kettle black. I correctly surmised you were being disingenuous about being a Linux user, which you admittedly were; as you do not play games on Linux. You are a Windows gamer, not a Linux gamer.

As you have no stake in the outcome of this discussion, the only conceivable motivation you could have had for commenting on this bug report was trolling. Thank you for your “contribution”; I will be running on Linux when we meet in Vermintide 2.

Valve itself wants Windows games to run on Linux (and MacOS), which is why they have integrated Wine ( https://www.winehq.org/ ) into Steam using their Proton project ( https://github.com/ValveSoftware/Proton/ ). Just enable Proton by navigating to ‘View -> Settings -> Steam Play’ in the Linux Steam client and checking all the boxes. Then you can download, install and launch Windows games from Steam on Linux.

Gaming on Linux is much easier than 10 years ago; the DXVK project ( https://github.com/doitsujin/dxvk ), which translates DirectX 11 calls to Vulkan ones, allows games on Wine to be played with near performance parity to Windows.

As for getting started, just install Ubuntu (the most user friendly distribution) and take it from there. Vermintide 1 fully works since it does not have Easy Anti-Cheat, give it a try.


Thank you a lot!

I’m here to support the Itzamna efforts, Vermintide 2 runs on Steam Proton (linux) this is not a question of which OS it’s supported, it’s a question that Easy Anti-Cheat services are blocking players. Itzamna has made acknowledged, Easy Anti-Cheat service has done solutions for WINE (PROTON) before as request from the developers, can you sort this out and simply ask for Easy Anti-Cheat service to offer, as it did already, support for WINE ?

1 Like

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Why not join the Fatshark Discord https://discord.gg/K6gyMpu