Thanks for taking a stab at answering the question.
Actually, vmnet0 is the network interface for the guest virtual machine. VMware acts as a NAT router by default. For example, my current IP address on my Mac is 10.10.10.139. Within the virtual machine, the IP address is 192.168.222.128. Because of this NAT arrangement, the guest VM can’t ping the host.

By adding “en0″ to the end of the vmnet-bridge command, the vmnet0 interface is bound (if that is the right word) to the Ethernet interface on my Mac. Once VMware’s vmware-vmx program is restarted (via the boot.sh command), the VMware guest machine is on the same “network” as the host machine. At this point my Mac can ping the guest OS, and vice versa.

Making this change is necessary to put the guest OS (in my case Windows XP) on the same network as the machine I want to acquire evidence from via the cross-over cable. Once I have connected my Mac via the cross-over cable to the target machine (the machine I want to acquire evidence from), the target machine, the guest OS (running EnCase), and my Mac can all ping each over.

Essentially, this set up is the same as if I connected the target machine, the Mac, and an XP machine to a switch, and configured all three machines to use the same subnet.

I hope this makes sense. I picked up this trick in the VMware forums here:

http://communities.vmware.com/thread/107821

AFAIK he’s changing the way VMware Fusion is setting up the network bridge .. the original file is setting up the bridge (vmnet0) to the first interface the MAC is connected to (e.g. … vmnet0 ”). He’s changing that to hard wire the bridge to en0 (vmnet0 en0) - i guess it is necessary to avoid that the wrong interface is bound to the bridge. After the change te bridge is hard wired to en0 aka your first network port on your mac