Hyper-V: Avoid using legacy network adapters when the guest operating system supports network adapters

Applies To: Windows Server 2008 R2, Windows Server 2012

This topic is intended to address a specific issue identified by a Best Practices Analyzer scan. You should apply the information in this topic only to computers that have had the Hyper-V Best Practices Analyzer run against them and are experiencing the issue addressed by this topic. For more information about best practices and scans, see Best Practices Analyzer.

Operating System

Windows Server 2012 or Windows Server 2008 R2

Product/Feature

Hyper-V

Severity

Severity level

Category

Issue type

Issue

A guest operating system that supports a network adapter is configured with a legacy network adapter. This configuration is not recommended.

Hyper-V provides two types of virtual network adapters—a network adapter and a legacy network adapter. A network adapter requires a virtual machine driver in order to work, but offers better performance.

Impact

Networking performance may be degraded for the following virtual machines: <list of virtual machine names>

Resolution

Use Hyper-V Manager to shut down the virtual machine and remove the legacy network adapter. If the virtual machine needs network connectivity, it requires at least one network adapter. If integration services are available, make sure they are installed.

By default, membership in the local Administrators group, or equivalent, is the minimum required to complete this procedure. However, an administrator can use Authorization Manager to modify the authorization policy so that a user or group of users can complete this procedure. For more information, see Using Authorization Manager for Hyper-V Security (http://go.microsoft.com/fwlink/?LinkId=142886).

Note

Integration services are included in Windows Server 2008 R2 and Windows 7. For all other operating systems, integration services are installed after you install the guest operating system. Integration services include the virtual machine driver required to use the network adapter.

To remove a legacy network adapter

  1. Open Hyper-V Manager. Click Start, point to Administrative Tools, and then click Hyper-V Manager.

  2. In the results pane, under Virtual Machines, find the virtual machine that you want to configure. The state of the virtual machine should be listed as Off. If it is not, right-click the virtual machine and then click Shut Down.

  3. In the Action pane, under the virtual machine name, click Settings.

  4. In the navigation pane, click the name of the network adapter.

  5. On the Legacy Network Adapter page, click Remove.

  6. If you do not want to add a network adapter, click OK. Otherwise, click Apply and continue to the next procedure.

To add a network adapter

  1. In the Settings dialog box, in the navigation pane, click Add Hardware.

  2. On the Add Hardware page, select Network Adapter.

  3. Click Add. The Network Adapter page appears.

  4. Under Network, select the virtual network you want to connect to.

  5. If you want to configure a static MAC address or virtual LAN identifier, specify the numbers you want to use.

  6. Click OK.