Arduino - IP display

I want to build an Arduino project that when plugged into my network via Ethernet, will quickly display the IP associated to the network drop.
Have any of you seen or done anything like this?

Not sure what you mean by "network drop".

Do you want the IP of the arduino or the external IP of the network?

If it's the latter the easiest method is probably to visit a web site that lists it (or make one, it's really easy in PHP) and grab the data.

The IP the Arduino is offerred.
i.e ipconfig / ifconfig results...

That would require the Arduino to grab an IP by DHCP and it would not be the same IP if something else were plugged into that "network drop"

That is fine, I just want it to quickly verify which subnet is attached to each LAN drop. I can identify the subnet/VLAN but the octet series

DHCP isn't supported by the current (outdated) ethernet library...

DHCP isn't supported by the current (outdated) ethernet library...

That (probably) means that you just have to write the code yourself at low level, making it a more difficult project. Sounds useful, though...