Configure Hyper‑V Virtual Switches: Enable NAT Networking for Linux VMs

Hyper‑V includes a built‑in manager for creating and managing local virtual machines. After creating a CentOS 7.9 VM and a Windows 11 VM, the Linux VM lacks network connectivity because no local network configuration is set.

Virtual Switch Manager

Hyper‑V networking consists of virtual network adapters and virtual switches. To enable communication, attach a virtual network adapter to a virtual switch.

The "Virtual Switch Manager" component can be opened from the server name context menu or the preview pane in Hyper‑V Manager.

Using the system default virtual switch "Default Switch" (internal NAT) as shown.

Virtual Switch Types

Hyper‑V provides three types of virtual switches:

Internal : Enables communication between each VM on the host and between VMs and the host.

External : Maps the virtual network to a specific physical network adapter (including wireless), allowing VMs to access external networks.

Private : Allows communication only among VMs on the same host; the host cannot communicate with the VMs.

Tips: You can assign a VLAN ID to a virtual switch to extend existing VLANs, and VLANs can be used to partition network traffic.

Configuring the Default Switch (NAT)

The Default Switch creates a NAT network where the VM receives a gateway and subnet mask from the host.

In Windows, the relevant adapters are "vEthernet (Default Switch)" and "vEthernet (WLAN)".

vEthernet (Default Switch) IPv4 Settings

vEthernet (WLAN) IPv4 Settings

You can also view adapter details with ipconfig /all.

Setting Up Network on a CentOS VM

The CentOS VM created by Hyper‑V has no network configuration by default.

Identify the network interface (usually eth0) with ip addr and edit /etc/sysconfig/network-scripts/ifcfg-eth0:

BOOTPROTO=static – set static IP

ONBOOT=yes – enable on boot

IPADDR=… – static IP in the same subnet as the virtual NIC

GATEWAY=… – gateway address

NETMASK=… – subnet mask

Configure DNS by editing /etc/resolv.conf to match the host’s DNS.

After editing, restart the network service: systemctl restart network.service Verify the configuration; connectivity tests show the VM can reach external networks.

Thus, using the Default Switch’s internal NAT mode and configuring the CentOS network completes the virtual machine networking setup.