Restrict Delphi 7 pgm to corporate LAN

Situation: i have a licencing program that i wrote in Delphi 7, this allows users to create licences for products that have been sold. There is a securi开发者_StackOverflow中文版ty risk with this because any employee could sell the products from home and take the licencing program home and create licences - they would be stealing and we would never know!

I thought it might be a good idea to restrict the licencing pgm to run only when its inside the corporate lan.

Is it advisable to do things like looking for the existance of a named server, or to test if its being run on a particular subnet? And if so any examples would be welcome :)

There is one easy solution: Make it a web service or at least implement the license creation only on a an application that runs on one or more servers. This would allow everybody who can access the server(s) via network to create licenses. Outside of your network - protected by a firewall - no access is possible and therefore no-one can create licenses on his/her own.

One thing to include in the mix is the domain of the computer. Most businesses have a domain that will be harder to reproduce. For an app you are developing for internal use, you could check for presence of a number of servers too.