A LAN party via VPN. Allows games to discover each other through VPN like if they were in local network.
There are 3 main steps:
- Announcement. vpnparty notifies whole VPN network that you want to play.
- Discovery. vpnparty listens to replies. There should be a second computer willing to join the game.
- Retransmission. Once at least one peer discovered, vpnparty starts retransmitting broadcast packets to the peer(s).
There are two mechanisms for announcement/discovery working simultaneously:
- multicast. Efficient and nice way to discover peer.
- Advantage - announcement is the single packet. Minimalistic.
- Disadvantage - network requires additional configuration to support multicast packets. Multicast is not available in VPNs by default and most likely disabled in your case.
- UDP. Raw brute force. Announcement step sends packet to every IP address in range 255.255.255.0. If your peers are there, connection will be established.
- Advantage - works.
- Disadvantage - spams network with 255 packets (only once!).
Retransmission is simple. Capture broadcast packets using Npcap, replace broadcast IP address by peer IP address, send. Repeat for every peer.
- Download and install latest Npcap. Tested with versions 1.79 and 1.80. Any compatible should fit.
Important! Select
Install Npcap in WinPcap API-compatible Modecheckbox! - Compile (or get somewhere) binaries. See instruction below.
- Add vpnparty to your firewall exceptions. It needs UDP ports 54928 and 54929 by default.
- Run vpnparty without arguments. Just double-click. Should work as is.
You can adapt application behavior to your needs. Let's see some examples:
.\vpnparty --help shows detailed help message with examples.
.\vpnparty -b 10.0.0.15 10.0.0.22 manually specify peer IP addresses.
.\vpnparty -b 10.0.0.15 10.0.0.22 --no-multicast --no-udping if you know all your peers (let's say there are 3 players), feel free to disable both discovery mechanisms as redundant.
.\vpnparty --monochrome is useful if your command line doesn't support color output.
.\vpnparty -p 7654 retransmits only broadcast packets with destination port 7654. Useful if you know exact port that your game uses. By default all broadcast packets are retransmitted, which might be not desired. One more option is -p known, which is the synonym to -p 4549 6112 42801. See those ports below.
.\vpnparty -v=1 to see debug messages. Set -v=2 to see all processed packets. Useful for debug.
git clone [email protected]:tvladyslav/vpnparty.git
cd vpnparty
cargo build --release
cargo clippytarget\release will contain generator.exe and vpnparty.exe.
- generator.exe is the debug tool. It sends 2 broadcast packets (to ports 4549 and 6112) every second. See troubleshooting section for details.
- vpnparty.exe is the application that you need.
Q: wcap.dll was not found
A: Reinstall npcap and remember to select Install Npcap in WinPcap API-compatible Mode checkbox.
Q: I see the There are active virtual network adapters in your system. warning.
A: Please follow recommendations of the warning. As alternative, go to Control Panel\Network and Internet\Network Connections and disable devices with "v" prefix (like vEthernet). Virtual devices can capture game packets, they won't reach vpnparty and your peer as the consequence.
Q: I run application but still can't join friend's game lobby. Why?
A: Several suggestions:
- Go to
Control Panel\System and Security\Windows Defender Firewall\Allowed appsand allowvpnparty. Allow the app in any other firewall in your system. - Make sure that
vpnpartydiscovered the peer. You should see the line like<IP> joined the party!.vpnpartycan't resend packets to nowhere. - Turn on packet tracing using
.\vpnparty -v=2flag. You should see all captured packets, where first letter denotes: B = resent game-related broadcast packet, M = multicast peer discovery, U = UDP peer discovery.
Thanks Ratmir Karabut and his udp-broadcast-tunnel for inspiration.
GNU GPLv3