content management system - How to make your custom php CMS work only on a certain domain for a certain time?
I want to prevent coping my custom made CMS from domain to domain and I want that it is operable only on a doain that it is bought for and onluy for the period 1, 2 years from the purchase.
The code generation part is not a problem, but how to prevent it from modifying from hackers is the hardest part.
E.g. something like vBulletin protection. (I know it can be nulled too)
How to implement such thing into my CMS written in php?
I think it needs to be spread through the whole app on various places the variable check and masked in some ways, so the dependencies is not easy to detect and remove.
I know that it is very difficult and hard topic, so I appreciate some direction like book, web discussion or article.
Btw. connecting to my server and checking if the domain is ok is not an option, my servers could be down and the clients as a result of not possible connection too.