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Netplay

2026-08
Game
Technology
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Real love is when you enjoy peeing together on frogs.

—Imageboard Comment

Okori Makuri and Mikapyon playing retro video games.

"Netplay" (online multiplayer), when available, can be complex to set up.

Guides and tutorials are frequently out-of-date or miss critical info. Older solutions often stopped working or are not available anymore. There are myths and misunderstandings about what works and what does not. Contrary to popular belief, netplay between Linux and Windows works just fine.

Okori Makuri and I have been experimenting with netplay for various systems. This is our collection of notes to make it work!

In short:

Obviously, if a specific version is not listed it just means we did not try. This post will be silently updated from time to time. Security, operating system, router or emulator usage is not part of this post. Please consult the official(!) manuals on how to use each software safely.

RetroArch#

Any "deterministic" emulator cores should usually work. You can check the core documentation or via the RetroArch core info menu.

RetroArch versions that worked for us:

RetroArch cores that worked for us:

Several flawless sessions with over 4 hours uninterrupted netplay time! Average ping of about 80ms.

RetroArch and Core Versions#

All players should use the same RetroArch and core versions. Working with Void Linux host and Windows 11 client and vice-versa. All 64-bit x86.

Same ROM#

All players should use exactly the same ROM. (Ideally compare your checksums.) Can be a ZIP file depending on the core and your setup.

Port-Forwarding#

We use a direct IP peer-to-peer connection without Traversal Server. The hosting player should configure port-forwarding for their router. TCP and UDP (should be TCP only but we did not try).

Firewall#

The host should allow the port. Maybe test with firewall (temporarily) disabled (security risk).

Connect and Go!#

Setup netplay using the RetroArch menu (or config file). Enter the hosting players IP address and a game password if you all use one. The hosting player starts the game before anyone can connect. When the hosting player gives the "OK", the clients can connect. The clients manually load their ROM and play! By default there should be an on-screen notification on success.

Memo#

Press "t" to chat (with default hotkey). To swap controllers (with default hotkey):

  1. All players press "i" to switch to spectator mode.
  2. One player presses "i" to join as Player 1.
  3. The other player presses "i" to join as Player 2.

A ping display hotkey can also be configured if there is no default.

Dolphin#

This is for the main Dolphin release and not the RetroArch Dolphin core. The RetroArch and Dolphin projects differ in their design philosophies.

Dolphin versions that worked for us:

Tested games:

Several flawless sessions with over 4 hours uninterrupted netplay time! Average ping of about 60ms.

Dolphin Version#

All players should use the same Dolphin version. Tested with Void Linux client and Windows 11 host. All 64-bit x86.

Netplay-enabled Dolphin Build#

Official builds are working. It seems when building from source, a flag needs to be set to get the string. I did not investigate deeply but there seems to be an internal version string. When connecting, the netplay process seems to compare the internal versions. The GUI will vaguely inform about a version mismatch with no further info.

Same ISO#

All players should use exactly the same ISO. (Ideally compare your checksums.)

Port-Forwarding#

We use a direct IP peer-to-peer connection without Traversal Server. The hosting player should configure port-forwarding for their router.

Firewall#

The host should allow the port. Maybe test with firewall (temporarily) disabled (security risk).

Connect and Go!#

Setup netplay using the Dolphin menu. We use the hosts IP address but the shared code method should work too. The host starts a session before loading the game so anyone can join. Connected players will show up in the session's chat lobby. Only the hosting player has to start the game.

Memo#

Save files are written only for the host. Client save should be untouched. Try to use similar settings for graphics, emulation, etc. on all clients.

Mednafen#

Mednafen versions that worked for us:

Mednafen modules that worked for us:

Several flawless sessions with over 4 hours uninterrupted netplay time! With the server-based netplay design you may experience noticable input lag.

Mednafen Version#

All players should use the same Mednafen version. Working with Void Linux and Windows 11 clients. All 64-bit x86.

Same ROM#

All players should use exactly the same ROM. (Ideally compare your checksums.) Can be a ZIP file depending on the module (may need config).

Port-Forwarding#

No port-forwarding or firewall rule should be required.

Pick a Server#

All players connect to a dedicated server. The official(?) server address should be: netplay.fobby.net port 4046. Official source code for self-hosted servers is also available!

Connect and Go!#

Mednafen is command-line based without a GUI. The following are basic examples you can customize to your tastes.

Linux Bash:

mednafen -connect\
    -netplay.host 'netplay.fobby.net' -netplay.port '4046'\
    -netplay.nick 'DarkSephiroth666' -netplay.gamekey 'cowabunga'\
    '/path to/game.zip';

Windows Batch:

"Z:\path to\mednafen.exe" -connect ^
-netplay.host "netplay.fobby.net" -netplay.port "4046" ^
-netplay.nick "FallenVegetaDBZ" -netplay.gamekey "cowabunga" ^
"Z:\path to\game.zip"

Memo#

Default hotkeys:

Each netplay user configures controller 1 on their own client.

What about ...?#

Sadly not all systems have netplay support or are very limited.

Nintendo 64#

As far as I know, netplay only works (worked?) with Project64. I have last tried it over 10 years ago with heavy sync issues even on LAN. Project64 is only supported on Windows?

Using the Wii Virtual Console via Dolphin sounds like a better bet right now? However the game options might be limited drastically.

ZSNES or (standalone) Snes9x#

I have used both for netplay in the past with Windows XP. Each required a specific older build as new versions dropped netplay support. I do not know the current situation but Mednafen or RetroArch do the job.

Gameboy/Advance, etc. Link Cable#

Netplay does not magically turn systems with link cable multiplayer into 2P. One idea that I have not tried:

  1. Player 1 runs two emulator instances on their own system
  2. Player 1 connects both emulator instances using link cable emulation
  3. Player 1 hosts netplay with one of their two running emulator instances
  4. Player 2 connects via netplay with Player 1's netplay host instance
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