LAN Multiplayer: "Duplicate name", unclickable Accept, and Host-start sync failure

[Mangosniper]

Prerequisites

• I have searched for similar issues and confirmed this is not a duplicate

Game Version

• Command & Conquer Generals
• Command & Conquer Generals: Zero Hour
• Other (please specify below)

Operating System

• macOS
• Linux
• Other (please specify below)

Bug Description

I maintain a set of Linux laptops for retro LAN gaming. Previously, Generals Zero Hour LAN multiplayer worked perfectly using GeneralsX. However, upon setting up additional identical machines, LAN multiplayer completely broke across all nodes (including when re-testing with the original machine).

The core symptoms match the historical broken behavior of stock Generals ZH under Wine which I tried before I discovered this project:

• "Duplicate name already in game" error when attempting to join a lobby, despite distinct player names.
• Non-host players cannot click "Accept" in the lobby (button remains unclickable or unresponsive).
• When the host starts the match, non-host players do not see a countdown and are left behind in the lobby rather than joining the game.

Some additional infos:

• Hardware/Image: Restored from an identical Clonezilla image (same system state across testing)
• Network: Tested via both Wi-Fi and direct wired LAN
• Originally worked on: GeneralsX-Beta-15
• Issue observed on: 1.0.1 (Linux-GeneralsXZH.flatpak)
• Rolling back to GeneralsX-Beta-15 on the exact same OS image did not resolve the issue.
• Tested laptop-to-laptop as well as my desktop-to-laptop; the behavior persists regardless.

Since I did not find any similar issues in the repo I assume it might be a problem only with my setup (but it does not make much sense to me why it worked a few weeks ago. The laptops are equal due to the clonezilla image)

Reproduction Steps

Steps to Reproduce

• Launch GeneralsX ZH on two separate Linux devices on the same local network.
  

• Device A hosts a LAN Multiplayer lobby.
  

• Device B attempts to join the lobby.
  

• Observe e.g "Duplicate name" error after multiple join attempts or failure to accept/start or join the match.
  

Additional Context

Specs of my Laptops are

OS: Pop!_OS 22.04 LTS x86_6
Host: Latitude 5400
Kernel: 6.17.4-76061704-generic
Packages: 2089 (dpkg), 18 (flatpak)
Shell: bash 5.1.16
Resolution: 1920x1080
Terminal: /dev/pts/1
CPU: Intel i5-8365U (8) @ 4.100GHz
GPU: Intel WhiskeyLake-U GT2 [UHD Graphics 620]
Memory: 2999MiB / 7747MiB
Disk (/): 138G / 225G (65%)

They are all the same.

Specs of my PC

bazzite:stable
Linux 7.2.4-ogc3.1.fc44.x86_64
AMD Ryzen 7 5700X3D (16) @ 4.15 GHz
AMD Radeon RX 6700 XT [Discrete]
7.53 GiB / 31.24 GiB (24%)
1920x1080 in 23", 60 Hz [External]

[fbraz3]

Good catch. I will review the LAN lobby.

[Mangosniper]

Update: I realized that on my Laptops I had, despite them being connected via LAN, also still Wi-Fi activated. As soon as I disabled this, the issue was gone. For all the other old games I use that was never an issue, but it seems Generals ZH is very, very sensitive regarding the network.

[fbraz3]

Another great catch!

Having multiple active network interfaces (Wi-Fi and Ethernet) at the same time is definitely tripping up the engine's IP selection and discovery on Linux/macOS, causing it to see conflicting addresses and treat them as duplicate players.

I can't dive into this today, but I plan to look into fixing this interface handling as soon as I get the chance. Thanks a lot for investigating and sharing the workaround!

[fbraz3]

@Mangosniper could you please test from this build and confirm if the issue is solved?

https://github.com/fbraz3/GeneralsX/actions/runs/36647573516