The security set commands are used for configuring specific security settings on your server.
ALLOW-NULL-REALNAME - Doesn't let clients connect with a blank real-name field.
CHANNELONLY - Disable all private messages.
CLONE-KILL-MULTIPLIER - Set the clone kill multiplier.
DEFTRIGGER - Set the default trigger.
FLOOD - Manage the flood control settings for users.
GRANULARITY - Set the services warning granularity.
INVITE - Set how often people can send invites.
JOINUNMANAGED - Determine if users can join unmanaged channels.
JOINUNREGISTERED - Determine if useres can join unregistered channels.
LOGLEVEL - Server log output.
MAXBANS - Set the maximum ban list size for a room.
MAXCHANS - Set maximum number of rooms a user can join.
MINLIST - Set the minimum number of users a room needs to be included in the room list.
NEWCHAN - Determine who can create rooms on the server.
NOOP - Determine whether people get opped when joining rooms.
NOSPOOF - Turn on spoof protection on your server.
REASONS - Enable or disable quit and part messages from users in rooms.
STATS - Set stats on or off for users to see.
SUPERINVIS - Changes the behaviour of user mode +i (invisible).
USERNAMELENGTH - Set the maximum length a user name can be set to.
WHOCHAN - Create a more restrictive /who output for users.
/as help security set <topic>
These settings should be reviewed before a chat server is opened to the public. While you can change them while your server is in use, several of them will create changes visible to the users. With all such changes, some people will be confused and there will be a period of adjustment.