[raiguard][2.0.65] "UserVerificationMissing" error consistently on Archlinux 6.16.3

[Internet Explorer]

Dear Factorio Support Team,

I am writing to report a critical issue we have encountered with the Factorio dedicated server. Since upgrading the system’s Linux kernel from version 6.16.1 to 6.16.3(CLIENT-SIDE), we have been unable to connect to the Factorio server. The connection attempt results in repeated "UserVerificationMissing" errors in the server logs, causing clients to be refused despite correct server configuration.

We were able to consistently reproduce this problem with multiple users on different machines using the same kernel version 6.16.3. Downgrading the kernel back to 6.16.1 resolves the issue immediately, allowing connections without errors.

Here are some relevant details:

Factorio server version: 2.0.65(Not Working) 2.063(Not Working)
Operating System: Arch Linux
Kernel versions tested: 6.16.1 (working), 6.16.3 (broken)(We think this is an Security Patch)
Error message in logs: "Refusing connection ... UserVerificationMissing"
Configuration: Verified "verify_user_identity" and user verification settings are appropriate and unchanged
Issue reproducible on different client machines
Client Error: Sendto (IP ADDR:({178.200.192.223:34197})) failed (13: Permission denied)
Client Factorio will Crash when Connecting to Server

ServerLOG:

Code: Select all

4025.773 Refusing connection for address (IP ADDR:({5.146.196.221:6212})), username (Microsoft69Edge). UserVerificationMissing 
4029.840 ConnectionRequestReplyConfirm (type(ConnectionRequestReplyConfirm) ) from(IP ADDR:({5.146.196.221:6219})) 
4029.840 Refusing connection for address (IP ADDR:({5.146.196.221:6219})), username (Microsoft69Edge). UserVerificationMissing 
4030.323 ConnectionRequestReplyConfirm (type(ConnectionRequestReplyConfirm) ) from(IP ADDR:({5.146.196.221:6245})) 
4030.323 Info ServerRouter.cpp:465: Replying to connectionRequest for address(IP ADDR:({5.146.196.221:6245})). 
4030.323 Info ServerSynchronizer.cpp:594: nextHeartbeatSequenceNumber(241755) adding peer(10) 
4030.340 Info ServerMultiplayerManager.cpp:808: updateTick(272872) changing state from(InGame) to(InGameSavingMap) 
4030.390 Info ServerMultiplayerManager.cpp:978: updateTick(272872) received stateChanged peerID(10) oldState(Ready) newState(ConnectedWaitingForMap) 
4030.407 Info ServerMultiplayerManager.cpp:1039: UpdateTick(272872) Serving map(/home/factorio/factorio/temp/mp-save-9.zip) for peer(10) size(3485055) auxiliary(110) crc(518027673) 
4030.407 Info ServerMultiplayerManager.cpp:808: updateTick(272872) changing state from(InGameSavingMap) to(InGame)
4030.490 Info ServerMultiplayerManager.cpp:978: updateTick(272876) received stateChanged peerID(10) oldState(ConnectedWaitingForMap) newState(ConnectedDownloadingMap) 
4032.340 Info ServerMultiplayerManager.cpp:978: updateTick(272987) received stateChanged peerID(10) oldState(ConnectedDownloadingMap) newState(ConnectedLoadingMap) 
4032.440 Info ServerMultiplayerManager.cpp:978: updateTick(272993) received stateChanged peerID(10) oldState(ConnectedLoadingMap) newState(TryingToCatchUp) 
4032.657 Info ServerMultiplayerManager.cpp:978: updateTick(273006) received stateChanged peerID(10) oldState(TryingToCatchUp) newState(WaitingForCommandToStartSendingTickClosures)
4032.657 Info GameActionHandler.cpp:4559: UpdateTick (273006) processed PlayerJoinGame peerID(10) playerIndex(1) mode(connect) 
4032.723 Info ServerMultiplayerManager.cpp:978: updateTick(273010) received stateChanged peerID(10) oldState(WaitingForCommandToStartSendingTickClosures) newState(InGame) 
4054.774 Info ServerMultiplayerManager.cpp:1086: Disconnect notification for peer (10) 4054.774 Info ServerSynchronizer.cpp:613: nextHeartbeatSequenceNumber(243223) removing peer(10).

This appears to be a regression or an incompatibility introduced by kernel 6.16.3 affecting Factorio’s network or user verification subsystem.
We kindly request your investigation and assistance in resolving this issue. If you need any further logs or testing from our side, please let us know.
Thank you for your support and for creating such a great game.
Best regards,

Internet Explorer

[eugenekay]

Since upgrading the system’s Linux kernel from version 6.16.1 to 6.16.3(CLIENT-SIDE), we have been unable to connect to the Factorio server.

Client Error: Sendto (IP ADDR:({178.200.192.223:34197})) failed (13: Permission denied)

Error 13 indicates that the request to send packets was denied; the most common reason for this is attempting to use a Privileged Port (1-1024; not the case here) without root privileges, followed by improper SELinux labeling, insufficient user Capabilities / security ulimits… in rare cases, it could even be that the Address given is determined to be a “broadcast address” (all-high-bits in the last digits, after subtracting the Subnet prefix). I note that the server’s address is .223 - which could potentially be the “last address” in a /27 Subnet! Can you share the output of ip -4 net show from the Server and Client machines?

The server is behaving properly here, since the Client has missed sending the follow-up part of the handshake it is dropping the Client.

Was anything else updated besides the Kernel?

[Internet Explorer]

Hi,

here are the Infos from Server:
root@FactorioGegner:/home/factorio/factorio# ip -4 route show
default via 192.168.0.1 dev eth0
192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.60

here are the Infos from Client:
default via 192.168.1.1 dev enp5s0 proto dhcp src 192.168.1.109 metric 100
192.168.1.0/24 dev enp5s0 proto kernel scope link src 192.168.1.109 metric 100

Nothing Other was Updated!
and no 27 Subnet

[Internet Explorer]

We have fixed the bug we previously reported. The issue was related to the network MTU size. If anyone else encounters similar problems, try running the following command (replace enp10s0 with your network adapter's name, which can be found via ip a):

sudo ip link set enp10s0 mtu 1400
or, if the problem persists, try a lower value, e.g.
sudo ip link set enp10s0 mtu 1300

Hope this helps others dealing with similar network issues!