At the server end, it is indeed true that rollbacks are simple. If you keep a tight leash on your players there should be no problem. However, there normally is a problem. Problems come in two kinds:
1) Players feel that it was unfair in some way. Presumably only a subset of players get to retake the turn, and those players now have knowledge of the future. Anything skillful that they do in that turn is tainted by the thought that even the most honest of players can't help the subconscious effects of knowing stuff they shouldn't.
2) Players accidentally send in 2hs from the wrong version of reality. Consider the situation:
- Turn 24 is processed
- All players get turn 25. Some start working on their turns.
- The game is rolled back to turn 24, then hosted again to get to an ALTERNATE REALITY version of turn 25.
- Some players send in 2h files based on the first version of turn 25. Or even, they use the 2h they had started work on as a starting point when working on the new turn 25. This will cause CRAZY THINGS to happen. Dominions will not reject 2h files based on the alternate reality (correct game, correct turn number, all checks passed), but it will go a bit mad.
--
Here is the safest way to do a rollback. We'll carry on with the above example, where we're on turn 25 and roll back to turn 24.
- Contact the player who needs to redo his turn. Get him to send his 2h file for turn 24 to you (the admin).
- Rollback the server.
- Immediately send in the 2h file for the player who needed the rollback.
- Immediately force hosting. This is cunning because it avoids the server being in the rolled back state for any length of time, and eliminates any suggestion that any of the players who were not meant to resubmit their turns may have done so.
- Send a message to all players (via the llamaserver system so they get an e-mail and don't have to check the forum) telling them to DEFINITELY DELETE ALL 2h FILES. This is very important.
- The game can now continue as normal.
Hope that helps!
(And sorry I didn't reply to your PM ssj.)