How to suspend a parked domain using .htaccess rule

We can suspend a parked domain using Rewrite rule in .htaccess while keeping the main domain intact.
In .htaccess file, add the following.
RewriteCond %{HTTP_HOST} ^domainname.com$ [OR] RewriteCond %{HTTP_HOST} ^www.domainname.com$ RewriteRule ^(.*)$ http://serversIP/suspend.txt [R=301,L]

NOTE: create a suspend.txt right there in the servers doc root