I have node-locked licensing working, using the MAC address and system time. We're concerned that people will just edit their system date to extend a license, so I've tried getting the real date from an machine in the NTP pool. That works, but then obviously you can't use the product without being online, and it doesn't seem to be 100% reliable (I'm guessing the UDP packet never arrives/returns in some cases).
What's the standard approach here? Live with the changeable OS date? Run something on a web server that provides the time over TCP? I hear the BIOS date gets updated by the OS when you reboot, so perhaps there isn't any way to know for sure what the current date is without using the internet?
I know that licensing can never be completely secure, and I expect it to be cracked or torrented, but I don't want it to be as easy as changing the system date. Any ideas appreciated. Thanks