Since the official FlatOut forum seems to be down, I write this here.
I sneaked in some "secret" commandline parameters to enable online play, over internet.
It's quite simple. The host just starts the game with
The joiner joins with "flatout -join=ip" where ip is the ip of the host.
There are some other more advanced options too, especially useful for playing behind a NAT. But even theese basic options should work with the joiner behind a NAT. As long as he is not behind the same NAT as the host. If the host is behind a NAT, then the only option you can use is to use port forwarding.
In that case the joiner needs to add an additonal parameter, "-publicaddr=ip
If the host wants to change the port he can do so, in the options.cfg file in the savegame folder. In that case the joiners either need to join with "-join=ip
ort", or change the port in the options.cfg. The joiners can choose any port in the options.cfg, no matter what the host chooses.
The alternative commandline "-join=ip
ort" is also usable in another case. If the host can configure his router, and uses non one to one port forwarding. I can explain that in more detail later, if needed.
Additionally you can specify "-password=balbla" Both the host and all clients needs to use the same password in that case.
This is almost totally untested by Bugbear, or Empire, so we cant promise that it works.