Connecting to a Windows domain on another subnet

I’m running VMWare Fusion on my Macbook. In it is an instance of Windows XP. I have a Samba server on my network that is configured to be a domain controller. If I connect my Macbook to the wired network, VMWare Fusion will create a bridged network device and the XP instance gets its own IP address from my DHCP server.

Irritatingly, if I use the Airport wireless connection, the VMWare bridging doesn’t work. I get a message saying /dev/vmnet0 doesn’t exist. After a bit of reading and asking it seems this is because Airport cards don’t support promiscous mode, which is needed for VMWare’s bridging device.

So since the Windows instance then has to use NAT, it gets given an IP address for a tiny private network living in my Mac, which is totally unreachable from the outside world. Also it means any broadcast messages to discover network services won’t go out onto my real network. The main one being Windows saying “hello, is there a domain controller out there?”.

Took me ages to work out that putting the Samba server’s IP address into the WINS part of the XP instance’s network config solved that problem. I can now do a domain logon over a VMWare NAT connection that is using the Airport card in my Mac.

I still haven’t solved the issue where I need the domain controller to be reachable in order to log in at all. Since this is a laptop it’s a bit of a failure if I can’t log into it with the usual profile when not plugged into my network. I don’t want two profiles as this will cause a right mess of duplicate settings, and me having to configure everything twice. I also don’t want to point the local user’s profile at the cached copy of the network user’s local profile. Somehow my work laptop is configured to allow me to log into the domain, even when the PDC isn’t there.