Acting as if it were a real DHCP relay agent (IP Helper), this class will send a DHCPLEASEQUERY packet over IP to a remote DHCP server to inquire about all known lease information for a given IP address. I wrote this as part of a PHP based syslog replacement. Upon receiving a syslog message from a remote DHCP server, it sends a DHCPLEASEQUERY packet back to the DHCP server to inquire about the rest of the otherwise unknown information about the lease. It then takes that information, does a quick lookup in MySQL to find the user who has a DSL router with the MAC address involved and..wa-la. Now you have an actual session record that can be stored/updated in MySQL and can tell big brother things like who had IP xxx on a given date/time...etc. This functionality is crucial as an ISP and for those like us who migrate away from using Radius, session logging becomes quite difficult without something like this in place.