Use Virtualization in Windows Server 2012 - MCSA Windows Server 2012 R2: Installation and Configuration Study Guide - page 452

figUre 9.6 Virtual Network Manager

Using Virtual Switch Manager , you can create, manage, and delete virtual switches. You
can define the network type as external, internal only, or private.
External Any virtual machine connected to this virtual switch can access the physical
network. You would use this option if you want to allow your virtual machines to access,
for example, other servers on the network or the Internet. This option is used in production
environments where your clients connect directly to the virtual machines.
Internal This option allows virtual machines to communicate with each other as well as
the host system but not with the physical network. When you create an internal network, it
also creates a local area connection in Network Connections that allows the host machine
to communicate with the virtual machines. You can use this if you want to separate your
host's network from your virtual networks.
Private When you use this option, virtual machines can communicate with each other but not
with the host system or the physical network; thus, no network packets are hitting the wire.
You can use this to define internal virtual networks for test environments or labs, for example.
On the external and internal-only virtual networks, you also can enable virtual LAN
(VLAN) identification. You can use VLANs to partition your network into multiple
subnets using a VLAN ID. When you enable virtual LAN identification, the NIC that is