Cyberstudy
Supplementary — not from your PDF Intermediate ~45 min

Build an isolated practice network

Set up two virtual machines on a host-only network so you have a safe, segmented place for every other lab. Then prove it is isolated from your home network.

Environment

VirtualBox (free) on your own computer, with two Linux VMs (e.g. Ubuntu Server, or small distros like Alpine).

Before you start

  • Read Security Zones (p.119), Physical Isolation (p.125) and Architecture and Infrastructure Concepts (p.112).

You will

  • Create a host-only network
  • Connect two VMs to it
  • Show which zones can and can't reach each other

Steps

  1. 1

    In VirtualBox open File → Tools → Network Manager and create a Host-only network (e.g. 192.168.56.0/24). Turn its DHCP server on.

  2. 2

    Set each VM's network adapter to 'Host-only Adapter' on that network.

  3. 3

    Start both VMs and note their addresses with ip addr.

  4. 4

    From VM 1, ping VM 2's address. It should reply.

  5. 5

    From VM 1, try ping 8.8.8.8 or your home router's address. It should fail, which shows the segment is isolated.

  6. 6

    Draw a diagram of your home LAN, the host-only lab segment, and your PC between them. Label the trust zones and where traffic is allowed.

  7. 7

    Take a VM snapshot so later labs can start from a clean state.

Check your understanding

  • ?Which of the guide's security zone ideas does your lab segment represent?
  • ?How is a host-only network different from a true air gap?
  • ?Why are snapshots useful before and after a lab?