I have a client who has a former employer who has tried to connect through the company VPN (presumbably to procure Intellectual Property for his new employee). I found log entries showing the login failure, with the IP address from which the connection was attempted.

How can I track down the owner of this IP address? I imagine that it is owned by an ISP, but if it got to the courts, the ISP would be able to check their records of who had that address assigned at that time.