Remote Multiplayer
Overview
Remote multiplayer refers to the ability for two or more machines to play the same game over a network of cable link. While this was popularized by FPS death matches, the history of remote multiplayer dates back over a decade prior to this popularity. The earliest games often relied on a physical connection via the PC's serial port, also commonly referred to as a null-modem connection. Later titles however were able to use the IPX network structure and support 8 or more simultaneous players.
Process
When starting a game that supports remote multiplayer in an eXo project, the user will be asked if they wish to enable multiplayer. This will in turn call the network.bat file in the game's launch folder. The user will then be prompted as to if they will be the host or a client computer. Regardless of the number of players involved, only one should be the host.
Host
The host machine typically handles the connections, and often makes the decision as to any settings in the game. This may include maps\courses, match type, time limits, etc. The host machine will report it's LAN and WAN IP addresses. The host will provide the proper IP to the clients. If they are all on the same network, the LAN IP will work. However, if playing over the internet, the WAN IP will be used.
Please note, to play over the internet, the host machine should have it's port forwarded properly. For IPX this is going to be port 213, while for serial port\null modem games it will be port 5000. If you are unable to connect to your client machines, please sure these ports are open and forwarded on your router.
The host will be provided with step by step instructions before the game starts that describe how to setup and begin a multiplayer match. This is important, as the process can be cryptic with some older games.
Client
Upon choosing client the network.bat file will request the IP address of the host machine. The host should provide this to you once they have it. The client machine will then report success (or failure) if connecting via IPX. The client machine will then display step by step instructions on how to set up and join the multiplayer game. These are important to note, as the process may not be straight forward.
Testing Note
If you are interested in testing multiplayer on the same machine, you may launch the game twice. For the host machine, you may ignore the reported IP address and simply type 127.0.0.1 into the client. As this is always the home machine IP, the two instances of DOSBox will see each other, and you can test a multiplayer match locally.