FAQ multiplayer

From OpenTTD

Questions regarding multiplayer aspect of OpenTTD, e.g. joining the server, creating the server, playing the game..

Contents 1 Does multiplayer really work? 2 How many players can join an OpenTTD game? 3 How do I start a multiplayer game? 4 Does it work cross-platform? 5 What port does OpenTTD use? 6 Can I use a Dedicated Server to host a Game? 7 How much bandwidth does the game use? 8 I am having trouble with cheating. Help! 9 Are there any rules? 10 Can console commands be executed automatically? 11 I started a new server. However, my game doesn't show up in my friends' game list, even after inserting the server manually on the list. Why does this happen?

[edit] Does multiplayer really work?

• Yes, multiplayer is stable since version 0.3.5. Up until that version it was almost impossible to play multiplayer games due to the bad network design of the original TTD.

[edit] How many players can join an OpenTTD game?

• Up to 10 players can participate in a multiplayer game. You can only open up 8 companies though. Each player can either play his own company, join another company (cooperative gameplay) or watch a game (spectator mode).

[edit] How do I start a multiplayer game?

• You can either do that through the multiplayer window or by using the following command line syntax:

openttd -n IP[:port][#playerID]

Example:

openttd -n 192.168.0.1:3979#1

would connect to 192.168.0.1 on port 3979 and joins as player 1.

[edit] Does it work cross-platform?

• Yes. You could, for example, start a server on MacOS and players using Windows, Linux or any other system can join.

[edit] What port does OpenTTD use?

• the default port is 3979, but you can change it to anything you like when you start a server. If you set up your own server behind a router, you need to forward both TCP and UDP on that port.
• Communication with the master-server works via port 3979 over UDP (inbound + outbound) and 3978 over UDP (outbound)
• If you are joining a server you do not need to forward any ports, as connections are outbound only.

[edit] Can I use a Dedicated Server to host a Game?

• It is possible to run a Dedicated Server using the '-D' switch. Click here for more details.

[edit] How much bandwidth does the game use?

• The rate is approximately 1.2 kbyte/sec upload and 1.2 kbyte/sec download per client. Multiplying that up, a 10-player server will use approximately 12 kbyte/sec up and 12 kbyte/sec down (the exact numbers will depend on the number of retransmissions etc.). Therefore, a 10-player, 24/7 server will consume 60 Gbyte/per month of bandwidth if all 10 players are connected the whole month.

[edit] I am having trouble with cheating. Help!

• There is a guide to shielding yourself from the worst elements of multiplayer cheating. Also, check the Multiplayer Rules.

[edit] Are there any rules?

• There are some rules, yes. You can see them here. Unfortunately the servers are not run by the OpenTTD Team, and they have no control over them whatsoever. As such if you have any problems you should contact the person who runs the server.

[edit] Can console commands be executed automatically?

• Yes, this is possible, and can be pretty handy. The page Running Startup Scripts will explain this in more detail.

[edit] I started a new server. However, my game doesn't show up in my friends' game list, even after inserting the server manually on the list. Why does this happen?

• There seems to be a problem when starting a new server from a computer connected to Internet via a modem that can be connected to multiple computers.