This mod puts the server into temporary maintenance mode on admin request. If any player without server or privs privileges attempts to join during maintenance, they will be rejected for an optional reason.
Whether the server is in maintenance is controlled by the existence of <world>/lockdown.txt; if present, its content is the reason for maintenance. It can also be controlled by a chatcommand (/lockdown on/off [<reason>]).
Hmm...
Not bad, however, this mod doesnt kick players who arent admins when lockdown turns on. Personally, i would register another privelege instead of using server or privs because, maybe you want moderators or map creators to be able to join. You probably dont want to give them the server or privs priveleges.