What Is A Virtual Switch?

What Is A Virtual Switch And How To Create A Virtual Switch For Virtual Machines?

Herbert Huffner Network July 19, 2021

A Virtual Switch Is A Software Program That Allows One Virtual Machine To Communicate With Another Machine. Like A Physical Ethernet Switch, A Virtual Switch Is More Useful For Data Transmission.

Virtual Switch, A virtual switch can manage intelligent communications over a network by inspecting packets before sending them to their destination. Some virtual switch manufacturers put their software inside the virtualization package, but a virtual switch can be embedded in the server hardware as middleware.

One of the biggest challenges with virtual servers is when network administrators try to get virtual machines back on physical hosts without configuring them again. Because transferring virtual machines to physical hosts in a way that maintains scalability takes time and, if not done properly, leads to security vulnerabilities, most organizations prefer not to go too far into the topic of virtualization.

This is exactly where the virtual switch comes in to solve the problem and come to the aid of organizations. Because it is a smart virtual switch, it allows organizations to make the best arrangements to ensure the integrity of virtual machines, security settings, network configuration, and virtual machines’ integrity when transmitting over a network to different physical hosts.

Today, leading companies such as VMware market various powerful virtual switches.

Meanwhile, Microsoft’s virtual switch with powerful capabilities, ease of use, and no need to download and purchase special software is a bit abandoned. The Microsoft Virtual Switch is located inside the Hyper-V Hypervisor. A tool used to build virtual machines. This article will learn how to build a Hyper-V virtual switch to connect virtual machines to a virtual network and other machines.

People new to networking, especially virtualization, face various difficulties, such as properly configuring the network and understanding the concepts. Networking in Hyper-V is different from other hypervisors, and even people with years of experience in virtualization may have some trouble getting their first contact with Hyper-V. In this article, you will get acquainted with the conceptual design of virtual networking in Hyper-V, its settings, and solutions for better implementation.

Hyper-V Virtual Switch

The Hyper-V Virtual Switch is a Layer 2 Ethernet network switch inside the Hyper-V Manager tool installed on a physical machine and the Hyper-V server role. The virtual switch directs packets to the meta-address, manages virtual local area network tags, and can even provide some features such as service (QoS).

This tool allows for connecting virtual machines to private and physical networks. Of course, a software development kit for managing this tool is provided for programmers. In addition, the Hyper-V Virtual Switch offers powerful governance policies for isolation, security, traffic guidance, protection against malicious virtual machines, simple debugging, and service delivery at various levels.

However, the Hyper-V Virtual Switch only supports Ethernet and does not support other technologies available on local area networks, such as Infiniband and Fiber Channels.

Microsoft Virtual Switch, because it can support Windows Filtering Platform and Network Device Interface Specification drivers by default, allows any standalone software developer to develop extensions called Virtual Switch Extensions for Hyper-Switch Created to improve network performance and security.

A virtual machine with a virtual network card can be connected to the Hyper-V Switch via the switch port.

What are the main features of Hyper-V Virtual Switch?

The most important features of the Hyper-V Virtual Switch that make you want to use it are:

ARP / ND Poisoning (spoofing) protection: Provides a powerful layer of protection against a malicious virtual machine. A malicious virtual machine can use the ARP (Address Resolution Protocol) protocol to eavesdrop on the IP addresses of other virtual machines. Using the Neighbor Discovery spoofing technique, the ARP / ND Poisoning protection mechanism protects machines from attacks that may endanger a virtual machine via the IPv6 protocol.
DHCP Guard protection: This creates a layer of protection around virtual machines. In this case, it fails if a malicious virtual machine tries to present itself as a Dynamic Host Configuration Protocol (DHCP) server and seeks to assign a malicious IP address to other machines or implements a middleman attack. Will be.
Port ACLs: Provide a consistent solution for filtering traffic based on MAC (Media Access Control) MAC addresses or IP addresses/address range that allows an isolated virtual network.
Virtual Machine Terminal Mode: Allows network administrators to configure a specific virtual machine as a virtual machine and direct traffic directly from the virtual local area network (VLAN) to the virtual machine.
Network Traffic Monitoring: Allows administrators to monitor traffic transmitted from the network switch.
Bandwidth limitation: Bandwidth limitation ensures that the reserved bandwidth is under the network administrator’s control and that the allocation process is performed accurately.

How to create a virtual switch for Hyper-V virtual machines?

The technique below can run on Windows 10, Windows Server 2016, Windows Server 2019, Microsoft Hyper-V Server 2016, and Microsoft Hyper-V Server 2019 operating systems.

A virtual switch allows machines built on Hyper-V to communicate with each other. When installing a Hyper-V role on a Windows server, you can create a virtual switch. If you want to implement a large virtual network that requires more virtual switches, you should use Hyper-V Manager or Windows PowerShell to build more switches.

Networks of virtual machines can quickly become complex, especially when you plan to use advanced features such as SET (Switch Embedded Teaming). Implementing and managing a virtual network based on a proper, step-by-step scheme will not be complicated.

Figure 1 shows a relatively accurate picture of how the Hyper V virtual switch is built and interacts with the physical network adapter. Follow these steps to build a simple virtual network with Hyper-V:

Figure 1. How the virtual switch interacts with the machine’s virtual network cards, virtual switch, and physical network

1. Open Hyper-V Manager and select the host computer name in the left panel.

2. Right-click on the computer name and select Virtual Switch Manager. (figure 2)

Figure 2. Hyper-V software main window

Figure 3. Virtual internal, external, and private switches are used for specific purposes.

3. In this step, you must specify the type of virtual switch. Hyper-V lets you choose one of the following three options to build a virtual switch.

External: External virtual switches allow virtual machines to communicate with servers and clients on an external network by accessing the physical network while communicating with virtual machines on the same Hyper-V server. An external switch must be connected to a physical adapter. This switch allows communication between the physical network, the operating system, and the virtual adapters used by the virtual machines. Be careful not to confuse the external switch with the public IP addressing scheme or Internet-based systems that must be connected to the Internet for proper operation. You can use the same range of private IP addresses for adapters on an external virtual switch that you attach to a physical network to which they are attached.
Private: A private switch that allows virtual machines to communicate with each other only on the host machine or, more precisely, the server on which Hyper-V is installed. This option is ideal for organizations looking for an isolated private network. A network that has no interaction with external network traffic. These include, for example, implementing a platform and environment for conducting experiments.
Internal: The function of the internal switch is very similar to that of a private switch, except that it allows the operating system to have a virtual adapter on the switch. The built-in switch allows virtual machines on the same Hyper-V server to communicate. It also allows the host operating system to manage them. The operating system can use the internal switch to directly manage any virtual machine with a virtual adapter. Like the private switch, the internal switch has nothing to do with the physical adapter.

Figure 4. Assign a name to the virtual switch for ease of operation.

4. Select the default External option and select the Create Virtual Switch button.

5. Assign a name to the virtual switch.

6. If you have selected the External option, you must now specify the network adapter (NIC) you intend to use, along with other related parameters.

When choosing External mode, pay attention to two important options related to this switch:

Allow the management operating system to share this network adapter:

Enable this option if you want to allow the Hyper-V host to share the virtual switch and network card it uses with virtual machines. Once enabled, the host can use any configuration applied to the virtual switch, such as Quality of Service (QoS) settings, security settings, or other Hyper-V virtual switch features.

Figure 5. You may lose access to the Internet for a few moments while building a virtual switch.

Figure 6. As you can see, the various adapters are shown with their speed and MAC address.

Enable single-root I / O virtualization (SR-IOV): Enable this option when you want virtual machine traffic to communicate directly with the physical network card, regardless of the virtual switch.

7. If you want network traffic to be isolated from other virtual machines with which the virtual switch is shared or from the Hyper-V management tool on the host operating system, the option:

Enable Virtual LAN Identification For Management Operating System

Enable. You can change the VLAN ID value or accept the default value. This value is the local virtual network identification number the operating system manages and communicates via the virtual switch.

8. Click Ok.

9. Pressing the Ok button displays a warning message announcing that your computer may disconnect until changes are made. Changes that may overwrite static settings. Click the Yes button. By pressing the Yes button, the virtual switch is ready to use.

Build a virtual switch through Windows PowerShell.

Windows suggests a second solution: the Power Shell window to build a virtual switch. Follow the steps below to build a virtual Hyper-V switch via the command line.

Click the Start button on the desktop and type Windows PowerShell in the Windows 10 search box.
Right-click on the found option and select Run as Administrator.
Find your current network adapter by running the Get-NetAdapter command. By executing the above command, all the installed adapters on your system will display along with their specifications and address.
The New-VMSwitch command builds a virtual switch in the PowerShell environment. For example, if you want to create an external virtual switch called ExternalSwitch, use the network Ethernet adapter, and enable the adapter sharing feature via the operating system, run the following command.

New-VMSwitch -name ExternalSwitch -NetAdapterName Ethernet -AllowManagementOS $ true

The following command is used to build an internal switch:

New-VMSwitch -name InternalSwitch -SwitchType Internal

A private switch is created by running the following command:

New-VMSwitch -name PrivateSwitch -SwitchType Private

It does not matter if you use a graphical or command-line environment to build a virtual switch. Both options allow you to create virtual switches, connect virtual machines according to the network schema you have created, and make the most of the benefits of network and switch virtualization.

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