I don't know about a database, if you find one or make one, please post it here. But you can often get the information out of DNS. I'm on a Windows machine rig

I don't know about a database, if you find one or make one, please post it here. But you can often get the information out of DNS. I'm on a Windows machine right now, so for example "ping -a" is your proof of concept. Basically you just want to resolve IP addresses to hostnames. You're foobarred though if someone works from home or uses the internet away from the office...