Your network contains an Active Directory domain named contoso.com. The domain contains a member server named Server1. Server1 runs Windows Server 2012 R2 and has the Hyper-V server role installed.
You create an external virtual switch named Switch1. Switch1 has the following configurations:
Connection type: External network
Single-root I/O virtualization (SR-IOV): Enabled
Ten virtual machines connect to Switch1.
You need to ensure that all of the virtual machines that connect to Switch1 are isolated from the external network and can connect to each other only. The solution must minimize network downtime for the virtual machines.
What should you do?（）

You have a server named Server1 that runs Windows Server 2012 R2. Server1 has the Hyper-V server role installed.
An iSCSI SAN is available on the network.
Server1 hosts four virtual machines named VM1, VM2, VM3, VM4.
You create a LUN on the SAN.
You need to provide VM1 with access to the LUN. The solution must prevent other virtual machines from accessing the LUN.
What should you configure?（）