How to disable the changing of dns settings?

I am addicted to porn and found a way to block it via dns, but i can easily change it so i need to block the ability to change dns settings so i can stop.|||if your running a windows box, look into windows policies. however if you have administrative rights on your machine to create policies, then those can be changed too. Why don%26#039;t you see if you%26#039;re ISP has something to offer, like a filtering service, you have to pay for it, but maybe they can handle the filtering upstream from you without your intervention.