Turn Maintenance Mode On/Off
This setting takes the web site offline or places it back online. It is useful if you are making major changes to the web site such as an upgrade.
When maintenance mode is turned on, any user browsing to your web site will receive the configured message telling them the site if offline. Only those uses with administrative access will be allows to log on and then view the site. Site Administrators will have full access to the site once logged on in maintenance mode.
Selecting the command again, will bring the site back online.