I have the following problem: My University requires that all PCs have their MAC address registered to a given Ethernet jack before they are allowed on the network. I have done this with my PC, which now obtains it's IP via DHCP and goes online just fine.
However, I am now trying to interject a router with NAT between my PC and my Ethernet jack so that I can hook up additional devices. To make this possible, I cloned my PC's MAC address into the router and gave the router the same "host name" as my windows 2000 machine.
This worked fine for a while: My router was served the same IP as my PC would, and all was fine. But it stopped working at some point. Strangely, while my PC is still accepted on the network, my router isn't.
I can't understand how the two are different. I thought that by cloning the MAC and clientID (= host name?) I would have made the two devices virtually indistinguishable, but apparently not so.
Here is my question: Can I spy on the DHCP negotiation, and if so, then how? To be precise, I want to see what is relayed across my Ethernet jack when the IP is negotiated via DHCP. Ideally, this should show me the differences between my router and my PC.
Alternatively, I would like to be able to set up a third computer as a would-be DHCP server. I could then use a crossover cable and plug the device in question into my mock-up DHCP server, and hopefully see how the device reports/identifies itself. I would then compare how my PC IDs itself, and how my router IDs itself on its WAN side. What software would be able to tell me in extensive detail how a device reports itself to obtain an IP via DHCP?
Quick answers are greatly appreciated! Thanks!!