The process of adding an addon domain involves the creation of the corresponding subdomain. In terms of Apache VirtualHost entries, an addon is a parked domain on that subdomain.
There is no way to add an addon without a subdomain being created, this is the fundamental principle of cPanel architecture. Nevertheless, it is a common desire to make the links - addon.maindomain.com and maindomain.com/addon unavailable.
There are two ways to achieve this:
1. Redirect both links to a Not Found page using .htaccess which is to be placed into the addon domain web root directory:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_HOST} addon.maindomain.com$
RewriteRule ^(.*)$ "http://maindomain.com/404" [R=301,L]
</IfModule>
Make sure to update addon and main domain names correspondingly.
2. Point subdomains addon.maindomain.com and www.addon.maindomain.com to a non-working IP address, e.g., localhost (loopback address) 127.0.0.1 or just remove these DNS entries. It can be done in your cPanel account in the following way:
Go to your cPanel account > Domains section > Zone Editor menu:
Click Manage next to the main domain name:
That's it!
