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Create a New Network Load Balancing Cluster

Applies To: Windows Server 2008 R2

To configure the Network Load Balancing (NLB) cluster, you must configure three types of the parameters:

  • Host parameters, which are specific to each host in a NLB cluster.

  • Cluster parameters, which apply to an NLB cluster as a whole.

  • Port rules, which control how the cluster functions. By default, a port rule equally balances all TCP/IP traffic across all servers. Some applications may require different or additional port rules to operate correctly. For example, when using NLB in a Remote Desktop Services environment, you will need to modify these default rules.

You can also perform the task described in this procedure by using Windows PowerShell. For more information about using Windows PowerShell for NLB clusters, see

When you are using Network Load Balancing (NLB) Manager, you must be a member of the Administrators group on the host that you are configuring, or you must have been delegated the appropriate authority. If you are configuring a cluster or host by running NLB Manager from a computer that is not part of the cluster, you do not have to be a member of the Administrators group on that computer.

To create a new NLB cluster

  1. To open Network Load Balancing Manager, click Start, click Administrative Tools, and then click Network Load Balancing Manager. You can also open Network Load Balancing Manager by typing Nlbmgr at a command prompt.

  2. Right-click Network Load Balancing Clusters, and then click New Cluster.

  3. To connect to the host that is to be a part of the new cluster, in the Host text box, type the name of the host, and then click Connect.

  4. Select the interface that you want to use with the cluster, and then click Next. (The interface hosts the virtual IP address and receives the client traffic to load balance.)

  5. In Host Parameters, select a value in Priority (Unique host identifier). This parameter specifies a unique ID for each host. The host with the lowest numerical priority among the current members of the cluster handles all of the cluster's network traffic that is not covered by a port rule.

    You can override these priorities or provide load balancing for specific ranges of ports by specifying rules on the Port rules tab of the Network Load Balancing Properties dialog box.

    In Host Parameters, you can also add dedicated IP addresses, if necessary.

  6. Click Next to continue.

  7. In Cluster IP Addresses, click Add and type the cluster IP address that is shared by every host in the cluster. NLB adds this IP address to the TCP/IP stack on the selected interface of all hosts that are chosen to be part of the cluster.


NLB does not support Dynamic Host Configuration Protocol (DHCP). NLB disables DHCP on each interface that it configures, so the IP addresses must be static.

  1. Click Next to continue.

  2. In Cluster Parameters, select values in IP Address and Subnet mask (for IPv6 addresses, a subnet mask value is not needed). Type the full Internet name that users will use to access this NLB cluster.

  3. In Cluster operation mode, click Unicast to specify that a unicast media access control (MAC) address should be used for cluster operations. In unicast mode, the MAC address of the cluster is assigned to the network adapter of the computer, and the built-in MAC address of the network adapter is not used. We recommend that you accept the unicast default settings.

  4. Click Next to continue.

  5. In Port Rules, click Edit to modify the default port rules, if needed.

  6. To add more hosts to the cluster, right-click the new cluster, and then click Add Host to Cluster. Configure the host parameters (including host priority, dedicated IP addresses, and load weight) for the additional hosts by following the same instructions that you used to configure the initial host. Because you are adding hosts to an already configured cluster, all the cluster-wide parameters remain the same.

Additional considerations

Additional references

Overview of Network Load Balancing

Add a Host to the Network Load Balancing Cluster

Managing Network Load Balancing Clusters

Setting Network Load Balancing Parameters

Network Load Balancing Manager Properties