>ID() is in the VFP7 help. Looks like it's the same as SYS(0).
>
>
>>>What about them using something from the machine like SYS(0) or ID() to identify themselves?
>>
>>SYS(0) may not be unique across multiple domains or machines. And what is "ID()"?

ID() works in VFP6, too. But you can't bring up any help for it. You get a "missing operand" if you try "HELP ID()" or a "missing expression" if you try "HELP ID". There's nothing in help for it, anyways.