GULP-Do You Know Who Your Users Are...Really?

Columbia University uses the "Free Love" method of network IP management. When a machine is plugged into our network, it receives a real (not NAT-ed) IP address. Additionally, we do not use NAC or any type of registration system to pre-register MAC addresses connecting to our network. In place of these, we use a program called GULP (Grand Unified Logging Program) that derives the information collected by registration systems using authenticated log entries and DHCP. In addition to giving us an excellent picture of who is using our network from where, we can mine that data to discover things like missing students and compromised passwords.