Learn to configure a subdomain to a separate IP address. Very useful for sites with shopping carts who want store.theirsite.com to look like it's on the same server. Requirements: Cpanel Control Panel and WHM access.
Example: domainame.com is hosted on server A but the shopping cart store is on server B. You need to make it look like domainname.com is also on server B. Setup a subdomain to point to a differernt ip address and voila!
1. Edit the Domains DNS Zone
Login to your WHM control panel or manually through SSH and edit a DNS zone, select the domain you wish to modify.
2. Adding the A Record
Create a new record for the subdomain Eg: Type in store for the name, select A record type and then type in the IP address you need it to mask to.
3. Ensure it Works
Make sure there isn't an actual subdomain created in the users account that you're trying to point to a different IP address or the pointer/mask will not work!