We are having a bit of a problem with this. I am not sure how to limit who can join via a whitelist. We are limited to the command line only and as far as I can tell, there is no real command to do it.

We are running a modified baystation12 server (based off tg station) and there is a option in DreamDaemon but I cant see a switch for that.

We have a git repo that we do update but I doubt that if we compile it on a windows machine it would most likely not work (but we could be wrong)

If anyone can help us with this that would be nice.
It's best done inside DM, overriding client/New() or similar, to check against a text file your game reads. It doesn't really need to be Linux specific, this strategy will work on Windows or Linux.