software detecting each other in lan

I have just developed a software in vb6, and almost ready for deployment, I need one feature.

As a way of curbing multiple installation in a network, i want the software to detect if another copy is installed within the same subnet, or lan network or all subnet belonging to one network.

Ca开发者_开发知识库n you give me ideas on how to implement this feature?

i know i might probably use winsock for the network stuff, but how?

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You can use IPv4 broadcasting or IPv6 multicasting to send a packet to a group (being all) of computers on the same subnet.

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People could easily circumvent your proposed security measure by turning on the Windows Firewall. The best anti-piracy measure would be to move from VB6 to a Web Application hosted on the cloud.. google SaaS.