Prevent Unparked Domains Resolving on Dedicated IP

Hi I've seen a couple similar threads but couldn't find a solid resolution to what I'm experiencing If I set up an account in WHM "domain.com" and give it the dedicated IP "123.12.34.123" Then, I point an A record on "domain.com" to 123.12.34.123 I can see the website content on example.com and on 123.12.34.123 This is all fine and as expected, however... If I then register the domain "domain.com" and point an A record to 123.12.34.123 I can then access the whole website from somethingelse.com How can I prevent an unrelated third party domain from resolving the website on a dedicated IP? I need the solution to be server wide, there must be a way to switch this behaviour off and only resolve domains that have been added in to cPanel/WHM Thanks Craig