All VMs on a domain lose internet?

I am doing an exchange environment lab setup. I have a Win Svr 2003 DC, Win Svr 2003 Exchange(03), Win Svr 2008 Exchange(10). All of these are running through Hyper-V as VMs (Virtual Machines). All of these machines had internet connectivity after joining all the VMs to the domain (and pointing DNS IPs at the DC), and somewhere between or after installing Exch03, all my VMs lost internet connectivity. They can all still communicate to each other, and my host machine. My host machine has internet connectivity. Also note, I can make a copy of the VHD (Virtual Hard Drive) of ANY machine, and boot by creating another VM, and the VM has internet connectivity.