The gateway IP address might be stable, but it's _nowhere_ near unique, just think about home routers -- all instances of any model default to the same IP address and are installed in thousands of locations.

There's just no reliable way to do this at the network level, it wasn't designed to do that, you need some sort of licence server. (yuk!).

In reply to Re^2: verify presence in a given network by RichardK
in thread verify presence in a given network by Anonymous Monk

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