Windows Virtual PC built-in DHCP server and ISA 2004

I was setting up a test Windows 2003 domain network to play around with it. One of servers is a gateway server – hosting ISA 2004.
network settings

However, I found an issue there – the “Internal Network” card did not get IP address from DHCP server (installed on domain controller in the local network), but instead an address from APIPA pool.
network status

The weird thing was, it said “Assigned by DHCP”, and the DHCP server itself had an IP address from APIPA range.
weird dhcp server.

I tried pinging this DHCP, sniff it etc. but with no results. Then I found some hint about a built-in DHCP server into Virtual PC. This DHCP server replies faster than my DHCP server on virtual domain controller, so it always won.

To remove this problem, you have to modify the System Policy Rule called “Allow DHCP replies from DHCP servers to ISA Server” to not allow the built-it DHCP server. To do this, go to ISA Server Management -> Firewall Policy and click “Edit System Policy” in Tasks pane. Go to DHCP rule (first one) and add a new exception.
system policy editor

Create a new computer with IP address and add it to excetions. This way the built-in DHCP server will not be allowed to assign IP address to your virtual NIC and it will get the IP from other DHCP servers in your network. Which is exactly what we wanted.

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  1. Handy info indeed. I ran into this problem trying to configure my environment for deployment services for my MCTS labs, and this was a great help. Another thing you can do (after much trawling on technet) is to edit the options.xml file in %localappdata%\microsoft\Windows Virtual PC\, there is an option in there to disable the DHCP for internal network.

    Internal Network


  2. Thanks a lot for this info, as the “add new policy” thing doesn’t work for client workstations.

    Anyway, I’m a happy VMWare Player user nowadays.

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