HOW TO: Better way to Enable WordPress maintenance mode

WordPress is a great tool. It has its own way of managing updates to your website – and will switch to maintenance mode automatically.  For the best user experience you should enable maintenance mode yourself.

How to Enable Maintenance Mode without a Plugin – method 1

Activating maintenance mode without a plugin is easy. First, open your FTP program and then navigate to the root folder of you WordPress install.
Then create a new file and change the name to .maintenance – WordPress looks for this file and automatically maintenance mode has been turned on.
Once you’re done, you just need to rename or delete the .maintenance file

Enable Maintenance mode & allow access to WP-Admin – method 2

The preferred option for maintenance is a bit more graceful. Any visitors to your site will see a short message and any logged in or Admin users will still have access.
This is probably the best solution – giving the most control to you the web developer.
So this time … create a new file and paste this code:
[php]
<?php
function is_user_logged_in() {
$loggedin = false;
foreach ( (array) $_COOKIE as $cookie => $value ) {
if ( stristr($cookie, ‘wordpress_logged_in_’) )
$loggedin = true;
}
return $loggedin;
}
if ( ! stristr($_SERVER[‘REQUEST_URI’], ‘/wp-admin’) && ! stristr($_SERVER[‘REQUEST_URI’], ‘/wp-login.php’) && ! is_user_logged_in() )
$upgrading = time();
?>
[/php]
Then just save the file and rename it to  .maintenance as and when you need it.  You’ll have a great tool now that can protect your website while you tinker under the hood.

WordPress Maintenance Mode