요기 보면 잘 나와있다
https://drupal.org/node/579624
<VirtualHost *:80>
DocumentRoot /www/myhome
ServerName *
...
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !\.(gif|png|jpg|jpeg|jfif|bmp|css|js)$ [NC]
RewriteCond %{REQUEST_URI} !=/underconstruction.html
RewriteRule ^ /underconstruction.html [R=301]
...
</VirtualHost>