Prevent access to folder of subdomain on main domain

Question

I have few websites on my host. Most of them have their own domain.

I want to prevent access to my subdomain folder via maindomain.com/subdomain .

I want to make it able to open only via subdomain.maindomain.com

Disable access if possible, or just redirect it to subdomain.

Answer 1

RewriteEngine on
RewriteBase / 

#if not already blog.website.com
RewriteCond %{HTTP_HOST} !^blog\.website\.com$ [NC] 
#if request is for blog/, go to blog.website.com
RewriteRule ^blog/$ http://blog.website.com [L,NC,R=301]