Interesting issue. Can you explain in a little more detail about your network. Do you have a DHCP server running on a Windows Server, or simply a router handing out DHCP IP addresses.
I'm wondering if the DHCP server is being confused by Windows 7 IPv6 DHCP Discover Packets or DHCP request packets. You could test this by turning off IPv6 in the properties of the network adapter on the Win 7 machines.
You might also take a look at any third party software running on the machines, I have found some mention of third party firewall software drivers causing similar issues.
If it's a Windows server providing DHCP you might take a look at this article http://technet.microsoft.com/en-us/library/cc779267(WS.10).aspx
A quick and dirty work around of course would be to turn off the DHCP client service on the machine and manually assign static values for the IP address configuration, either outside of your current scope, or create a couple reservations for the two problem machines within the scope. Certainly not ideal, but a temporary work around.
If they have multiple network interface cards, you probably should also disable the one(s) you are not using as multi-homed DHCP clients can cause this sort of thing.
I agree you should manually assign IP addresses to the corresponding MAC addresses within the DHCP config, for these faulty PCs; that's what I do due to some other reasons, and it worked fine so far with Windows 7.
Also this issue reminds me of a previous post where DHCP was also -potentially- conflicting with Win7. I'm interested to hear about the answer
I am using a 2003R2 server for DHCP, when I put my windows7 32bit, windows7 64bit, or 2008 server on the network the DHCP fills with BAD_ADDRESS messages. Only these three units are acting up. I turned off IPv6 days ago.
My DHCP server issues addresses for 192.168.2.xxx, an I have over 70 free address to work with. I have a statis network for printer and servers, 192.168.10.xxx. There are a number of subnets used for wireless devices that have there IP's assigned by a Cisco Router. But those networks do not work on our hardwired inforstructure.
When I assigned a static IP address, I still recieved an address conflict error. I am starting to wonder if a recent update has caused this issue.
I have read cc779267(WS.10) and I am not seeing an issue with the DHCP server.
I have read similar issues when using multiple interfaces (multihomed) on a single PC, hence single DHCP client. Briefly speaking, the PC tends to reply to DHCP's ICMP requests using the main interface instead of the corresponding one. Obviously, this leads to bad_address codes on the server.
Also, it is worth checking the MAC addresses for all these PCs, just in case some are redundant... I know they are supposed to be unique and static, however it is possible to modify a MAC address, although that is usually done on purpose...
Last option is to dump DHCP traffic and see what really happens between the server and the client, leading to a BAD_ADDRESS code.
Since you have a 2008 server available on the network, have you considered moving the DHCP Server service role, to the 2008 Server machine, I know it's not the solution, you're looking for and possibly not a solution at all, just an option. I know that we've seen and discussed issues with Windows 7 communications with a 2003 server, being used as a print server and the issues seemed to revolve around something relatively new from Microsoft called, "Asynchronous RPC"
you can google it and maybe get some understanding, but basically it's intended to speed up communications between Windows 7 clients and 2008 and 2008r2 servers. That particular issue for that member was to move his print server to a 2008 server on his network and the problem disappeared. Again not sure that this is an issue in your specfic case, just thought I might throw it out there for your consideration.