virtualbox.org

Hi, I've been using virtual box for a while now but have never really grasped the network card situation. I wondered if anyone here could give me a few pointers? Basically I am setting up a little network to test, I will have one domain controller running windows 2008 r2 and one client machine (to begin with) running windows 7. I want to be able to access the internet from both machines and believe I should have 2 network cards set up on the domain and one on the client, is this correct? If so which ones would I use?

No. Never put two network cards in a DC.

The best idea is to set up your domain in an internal network with private addresses and install a vm to act as a NAT router between the domain and your Internet connection. Consider using an appliance like PfSense in your router vm.

The router vm would be the machine with two network cards - one in the domain network (which is the gateway for that network) and one linked to the Internet. How you set that one up depends on how your host machine connects to the Internet.