Win32Whois

Win32Whois is a free, small and efficient tool that lets you retrieve registration information for a particular domain or website. It will take an URL, hostname or IP address and will generate a detailed report listing all the available technical and contact information it can find. The generated report can be saved as a file or used to track down website owners, administrators or spammers.

It has an internal list of servers that it connects to in order to provide a detailed report on a requested domain.