You can configure one or more virtual network adapters for a virtual machine. You can use this procedure when modifying a virtual machine or template or configuring hardware profile settings from the New Template Wizard or the New Virtual Machine Wizard.

1. You can configure virtual machines to use one or more virtual network adapters that connect the virtual machines to internal networks or to external networks after the virtual machines are deployed on a host. To add a virtual network adapter, in the left pane, click Network Adapters, click Network Adapter on the top menu, and then select one of the following:

   • Emulated network adapter
     
     Emulated network adapters are available on all of the virtualization software platforms and allow virtual machines to be connected to virtual networks. Virtual networks can be connected to other virtual machine network adapters and to host network interface cards.
     
     
   • Synthetic network adapter
     
     Synthetic devices are new with Hyper-V and provide better performance than emulated network adapters. Synthetic network adapters require Virtual Guest Services (VGS) to be installed on the virtual machine. VMM installs VGS for all supported guest operating systems.
     
     

2. In the left pane, click the network adapter, and then, in the results pane, configure the following options:

   1. Under Connect to, select the network switch to use for the virtual network adapter, and then specify the following connection requirements:
      
      
      • Network location. Select the network to which you want to connect the new virtual machine. This setting is used by placement to determine equivalence between virtual networks across different hosts. Virtual networks determine their location from the host network adapter associated with them. You can link multiple host network adapters to multiple virtual networks and have one address set as the location. This allows a virtual machine to move and retain the correct connectivity.
        
        
      • Network tag. A tag is a virtual network property that allows you to define precise constraints on the network access of a virtual machine. For example, a host may have two network adapters, both with connectivity to the same network, but one dedicated to a Backup network. The Backup virtual network can be configured to have "Backup" as its tag.
        
        
      • Port group. For VMware virtual machines only, and new in VMM 2008 R2, after selecting a network switch, select the port group to use on that switch. VMM surfaces the port groups configured in VirtualCenter for use with ESX Server hosts and virtual machines.
        
        
      • Enable virtual LAN identification To enable virtual LAN identification, optionally select this option and then specify a VLAN ID.
        
        
      • Enable virtual network optimizations. New in VMM 2008 R2, this option allows you to take advantage of network optimization capabilities that are available on Hyper-V hosts that are running Windows Server 2008 R2. For information about this feature and the hardware that supports it, see your Windows Server 2008 R2 documentation. After a virtual machine is deployed, this feature is displayed only for virtual machines deployed on a host running on Windows Server 2008 R2.
        
        
   2. Ethernet (MAC) address. Like the MAC address on physical computers, a virtual MAC address on virtual machines uniquely identifies each computer on the same subnet. The following options are available for MAC addresses:
      
      
      • Specify whether to use a dynamic MAC address or assign a static MAC address:
        
        
        • Dynamic. Select this option if you want to enable a dynamic MAC address for a virtual machine.
          
          
        • Static. Select this option if you want to specify a static MAC address for a virtual machine. Type a static MAC address in the field provided.
          
          

        Note
        You can assign a static MAC address from a pre-defined pool by selecting the Static radio button, and then clicking Generate. To change the MAC address range from the Administrator Console, in Administration view, click Networking, and then double-click Global Static MAC Address Range.

      • To allow the guest operating system of a Hyper-V virtual machine to provide an alternate MAC address to the one that the virtual machine provides, select the Enable spoofing of MAC addresses check box. This option is new in VMM 2008 R2. In Windows Server 2008, this capability is automatic in Hyper-V. To adhere to the “secure by default” principle, in Windows Server 2008 R2, the feature is turned off by default.
        
        Because no host has been selected during virtual machine creation, this option always is displayed in the New Virtual Machine Wizard. After a virtual machine has been deployed, the option is displayed only on virtual machines deployed on Hyper-V hosts running on Windows Server 2008 R2. Spoofing of MAC addresses is always available for Hyper-V virtual machines on Windows Server 2008–based computers
        
        

See Also