On this tab, you can set security-related properties of the message board.
If the Use security code (CAPTCHA) check-box is checked, users will have to retype the CAPTCHA security code before adding a new message.
The Allow comments to section can be used to define which users can add new messages to the board. The following options are available:
•All users - everyone can add messages to the board
•Only authenticated users - only signed-in users can add messages to the board
•Only authorized roles - only members of the roles in the list-box below can add messages to the board
The following two options can be set only for group message boards:
•Only group members - only members of the group can add messages to the board
•Only group admin - only administrators of the group can add messages to the board
Detailed information about the Message boards module can be found in Developer's Guide -> Modules -> Message boards.