>Folks, how do you synchronize workstation's datetime with server's datetime on the fly? This problem becomes urgent to us because some users tend to change their workstation's datetime and do something illegal so that if they're caught, they can easily blame the system.
I create a file on the server (it will have the server's date-time), check its date-time, and if the discrepancy is more than 10 minutes, I don't allow the user to start the system.
In your case, since the user might change the date/time after login, you have to check before saving time-critical information. If the discrepancy is too big, show a warning and don't allow the user to save the record.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)