If building a sandbox testing environment, which virtual switch should the VM be connected to?

When creating a sandbox testing environment, a virtual machine (VM) should be connected to a private virtual switch. This type of switch allows VMs to communicate only with each other while isolating them completely from any external network access. This setup is essential for sandbox environments, as it ensures that testing can be conducted safely without the risk of interference or exposure to outside networks, thereby protecting sensitive data and preventing any unintended interactions with other systems.

By using a private virtual switch, one can safely test new applications, configurations, or system changes, ensuring that these experiments do not affect production environments or other systems on the network. This level of isolation helps in troubleshooting and developing without the fear of causing disruptions or security breaches.

The other switch options provide varying levels of network connectivity and security, but they do not meet the specific requirement for a sandbox environment where isolation from outside interactions is paramount.