Whitelist, operators and bans

• /whitelist on — only listed players can join.
• /whitelist add <name> — add someone. Works even if they are offline.
• /op <name> — full operator. Give this out sparingly; an operator can do anything.
• /ban <name> <reason> and /pardon <name>.
• /ban-ip and /pardon-ip for the ones who come back with a new account.

All of these work from the panel console too, without the leading slash, which is handy when you are not in-game.