All customers can set reverse DNS entries for their VPS' IP addresses.

Click the Reverse DNS link in the Network section of your VPS' dashboard page to configure rDNS.

Alternatively, log into mPanel and browse to the following link and click Select to edit rDNS for that VPS

Please note that editing of your rDNS value will take upto 12 hours to update, this is important as mail blacklists such as 'SORBS' have specific values to determine a static IP Address.