In this post I will cover the basic set up of the basic building block network which is a simple flat network behind a router acting as Firewall, NAT, DHCP and VPN for the network.

The first action is to create a Virtual Switch that will be connectivity for all the virtual machines in this flat network. Almost all virtual solutions support having a virtual switch under one name or another. Since I choose for my home lab ESXi the commands shown will be for this platform but in general terms can be done the same with Hyper-V or XenServer. 

The main reason why I'm showing all the steps via command line is so that they can be automated later in a script if this is a process that will be repeated several times.