How To Set Up TCP/IP for Network Load Balancing in Windows Server 2003

This article describes how to set up Transmission Control Protocol/Internet Protocol (TCP/IP) for Network Load Balancing, which is typically the last step of a Network Load Balancing installation.

With Network Load Balancing, you can spread incoming requests across as many as 32 servers. With this feature, you can expand enterprise-wide services such as Web servers, Terminal Services, and streaming media servers, and you can make sure that they can respond quickly, even under heavy loads.

Network Load Balancing automatically detects the failure of a server, and then quickly reassigns client computer traffic among the remaining servers. This safeguard can help you to provide uninterrupted, continuous service for your critical business programs.

IMPORTANT: You can configure many network load balancing options in the Network Load Balancing Manager or in the Network Load Balancing Properties dialog box. (To view the Network Load Balancing Properties dialog box, start the Network Connections tool). Microsoft recommends that you use the Network Load Balancing Manager.

WARNING: Do not use both Network Load Balancing Manager and Network Connections to configure Network Load Balancing properties; this may produce unpredictable results. The Network Load Balancing Manager is the recommended tool for modifying network load balancing settings.

NOTE: If the IP addresses of the server are configured before Network Load Balancing configuration is complete, and the Network Load Balancing Manager is used to configure the cluster, you do not have to do step 6 of the "Set Up TCP/IP for Network Load Balancing on Multiple Network Adapters" section of this article.

Set Up TCP/IP for Network Load Balancing

You must use different procedures for single or multiple adapters.

NOTE: When you try to configure Network Load Balancing manually and you add the Cluster IP and subnet mask, you receive the following message:

Set Up TCP/IP for Network Load Balancing on a Single Network Adapter

1. Click Start, point to Control Panel, point to Network Connections, and then click the Local Area Connection on which Network Load Balancing is installed.
2. Click Properties.
3. In the Local Area Connection Properties dialog box, click Internet Protocol (TCP/IP), and then click Properties.
4. In the IP address box, type the address that you typed as the "Dedicated IP address" in the Network Load Balancing Properties dialog box under Host parameters. If the correct address is already present, do not change the address.
5. In the Subnet Mask box, type the subnet mask and the default gateway information for your TCP/IP network. Click Advanced, and then click Add.
6. Type the cluster IP address in the space for IP address, and then type the appropriate subnet mask and, if you have to, type the default gateway. This IP address corresponds to the "Cluster IP address" (formerly known as "Primary IP address") of the cluster that you typed in the Network Load Balancing Properties dialog box under Cluster parameters.
7. If you have to configure additional virtual IP addresses for your cluster (for example, if you are running a multihomed Web server), you can do so at this location in the Advanced TCP/IP Settings dialog box.

To Set Up TCP/IP for Network Load Balancing on Multiple Network Adapters

1. Click Start, point to Control Panel, point to Network Connections, and then click the Local Area Connection on which Network Load Balancing is installed.
2. Click Properties.
3. In the Local Area Connection Properties dialog box, click Internet Protocol (TCP/IP), and then click Properties.
4. In IP address, type the address that you typed as the "Cluster IP address" in the Network Load Balancing Properties dialog box under Cluster parameters. If the correct address is already present, do not change the address.
   
   NOTE: You can also type the dedicated IP address (that corresponds to the "Dedicated IP address" that you typed in the Network Load Balancing Properties dialog box under Host parameters) in this space, and then wait to type the primary IP address of the cluster in the Advanced TCP/IP Settings dialog box.
5. In Subnet Mask, type the subnet mask and the default gateway information for your TCP/IP network.
6. If you have to configure additional virtual IP addresses for your cluster (for example, if you are running a multihomed Web server), click Advanced, and then click Add. You can specify additional virtual IP addresses for this network adapter and provide other information.

Troubleshooting

• TCP/IP must be the only network protocol present on the cluster adapter. You must not add any other protocols (for example, Internetwork Packet Exchange [IPX]) to this adapter.
• You must type the dedicated IP address first, in the Internet Protocol (TCP/IP) Properties dialog box (not in the Advanced TCP/IP Settings dialog box), so that all outbound connections that are made on behalf of this host (for example, Telnet or File Transfer Protocol [FTP]) are initiated with this address.

If you are configuring Network Load Balancing in Windows Server 2003, Microsoft recommends that you search for "Network Load Balancing" in the Help files, and then follow the topic called: "Checklist: Enabling and Configuring Network Load Balancing". This topic provides valuable information and steps to successfully install and configure Network Load Balancing.