If you want to update your site, or do some maintenance stuff and you dont want to allow others to have access to your site
add the code below to your htaccess file in root of your folder.
The below code sends all users to maintenance.html EXCEPT those with the specified IP .. simply change the ip 11\.111\.111\.111 to the IP of your computer. Otherwise your pc will be blocked as well. And dont forget to add a maintenance.html file in your root with some information. and dont forget to change domain.com to your own domain name...
RewriteEngine On
RewriteBase /
RewriteCond %{REMOTE_ADDR} !^11\.111\.111\.111
RewriteCond %{REQUEST_URI} !^/maintenance\.html$
RewriteRule ^(.*)$ http://domain.com/maintenance.html [R=307,L]
