Re: DHCP - IP assign Control

From: x y (
Date: 06/08/02

From: "x y" <>
Date: Sat, 8 Jun 2002 16:36:20 -0400

I seem to remember reading that Windows 2000 DHCP server has a feature that
may allow you to only allow authorized computers IP addresses, but am not
sure about any vulnerabilities there. If this lockdown is done by MAC
address, MAC addresses can be spoofed. This feature is surely documented in
the help file on your server and also at and is
probably seen by right-clicking somewhere in your DHCP server.

I am not aware of anything native that would alert you to this, but there is
probably a windows 2000 server resource kit tool that could allow you to
export the MAC addresses from the DHCP database into an access or SQL
database [or maybe even a plain text file monitored by a batch file or
script] that could then be monitored by a batch file for new unrecognized
mac addresses. From there it would be up to you to try to locate the PC,
which could be tricky on a network of your size. someone here may have a
better answer, but I do not believe Windows 2000 allows this natively.

"Rui Brettes" <> wrote in message
> Hi!
> My question is about DHCP Service in W2K,
> I have a large network (almost 500 Client's) and i need to control, in a
> simple way, the access to the network.
> I need to have something tha warns me about instuders in my network.
> Ex. A client that only have a PC assigned to him and try to connect his
> laptop (not autorized) to lan. How i can know this is happening, in a real
> time mode??
> Could DHCP inform me?
> Can i read DHCP information in some applet?
> Do you know if exist aplications that can do this task?
> Best regards, and thanks
> Rui Brettes