masking a subdomain

[dejv]

currently when i write sub.domain.net, when the page loads it is showing the server ip so i need to mask it

my current .htaccess shows:

Code:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^sub.domain.net$ [OR]
RewriteCond %{HTTP_HOST} ^www.sub.domain.net$
RewriteRule ^(.*)$ http://***.***.***.***/folder_name/ [R=301,L]

what do i have to write more ? so that it will not show the ip /