Da Miracle was founded in 2009 by Debadrita Bose (June Ray).   

Follow the steps below to put your website under maintenance

Step-1: Create a ‘website under maintenance’ web page and name it as 503.php. Put following PHP code at the very top of the page before the <html> tag:
header(“HTTP/1.1 503 Service Temporarily Unavailable”);
header(“Status: 503 Service Temporarily Unavailable”);
header(“Retry-After: 3600″);

This code will return 503 response header which tells the search engine that your website is temporarily unavailable. The ‘Retry After’ parameter tells the search engines to try to crawl the website after 3600 seconds (or 1 hour).
Note: Google also recommends returning 503 status code when your website is under maintenance.
Also insert Google Analytics tracking code in the head section of the 503.php page to keep track of the website visitors during the downtime.

Step-2: Add following lines of code at the top, in your .htaccess file:
RewriteEngine on
RewriteCond %{REMOTE_ADDR} !^
RewriteCond %{REQUEST_URI} !/503.php$ [NC]
RewriteRule .* /503.php [R=302,L]

The code in the .htaccess file will redirect all the pages on your website to the 503.php page. So no matter what page a visitor access on your website, They will be automatically redirected to the 503.php page.