First, verify that NLB is installed on your server by right-clicking My Network Places, then selecting Properties. Right-click Local Area Connection, then select Properties. NLB should appear in the Components checked are used by this connection list. Now, follow the appropriate instructions for one or two NICs to set up NLB for the first time.
In the Local Area Connection Properties dialog box, select the Network Load Balancing Service check box, then click Properties. In the Network Load Balancing Properties dialog box, you configure settings for the cluster, the host, and the ports in use.
Configuring cluster parameters. To begin NLB configuration, click the Cluster Parameters tab, which Figure 2, page 9, shows. In the Cluster IP configuration section, enter the VIP address for the cluster. As you enter the IP address, notice that the network address changes with each octet you enter. This network address is really a MAC address that's permanently assigned to a NIC. (The NLB load-balancing mode that you select later determines what you do with this address.) Each octet is converted to its hexadecimal equivalent on the fly, creating that unique network MAC address. This uniqueness is important in a switched environment because some switches don't work well when more than one switched port claims to own the same network address. Some switches let you disable the system's ability to learn network MAC addresses.
Next, enter the appropriate subnet mask for the VIP address. (You'll supply the default gateway information later.) Then, in the Full Internet name text box, enter the cluster's Fully Qualified Domain Name (FQDNe.g., cluster.domain.com). Note that for a production server, you'll need to perform name resolution (e.g., DNS) on this FQDN before you put NLB into production.
Now you need to decide which cluster operation mode to useUnicast or Multicast. (Note that the first network adapter is always the cluster adapter.) Notice the IGMP multicast option. This option is useful only if you're using Multicast mode and NLB traffic is overwhelming your network switch.
If you want to let administrators use the NLB command-line tools to remotely administer the cluster, select the Allow remote control check box and provide a password. Enabling this option lets you perform simple administrative tasks for your NLB cluster, such as starting and stopping the cluster, removing a host from the cluster for maintenance, and displaying cluster diagnostics. Using this remote command-line option doesn't preclude your using Win2K Server Terminal Services to remotely administer the cluster.
Configuring host parameters. In the Network Load Balancing Properties dialog box, click the Host Parameters tab, which Figure 3, page 9, shows. First, configure the cluster host's Priority. This value determines the host's priority in the cluster. The lower the number, the more requests a cluster member tends to fulfill for a client. The default value is 1. If you plan to add additional hosts to a cluster, you'll need to increment those values accordingly. Next, enter the host adapter's dedicated IP address and subnet mask. Finally, you need to decide whether to set the initial cluster state to active. Selecting the Set initial host state to active check box tells NLB to insert the host into the cluster immediately.
Configuring port rules. Switch to the Port Rules tab, which Figure 4 shows. This tab lets you tune the load-balancing algorithm. You can filter requests based on ports, protocols, and client IP addresses. The default filter is for balancing any request for any ports within the range of 0 to 65,535 for both TCP- and UDP-based requests.
The filtering mode also influences which client answers a request. One option is to use multiple hosts and balance client requests among all cluster hosts. Another option is to use the Single mode to force all client requests to a specific cluster host until that host fails. On failure, the remaining hosts in the cluster use their Priority value to determine which cluster host assumes the traffic from the failed host. Another option is to tell the cluster not to service traffic for certain ports and protocols.
In the Multiple mode, affinity options help cluster hosts decide what traffic they should answer. (For more information about affinity, see "Load Balancing Down on the Web Farm.") The Class C option directs traffic from the same Class C address space to the same cluster host. Single mode ensures that all traffic from the same IP address reaches the same cluster host. If affinity is important to you, consider the Single option first. I use Single mode on my servers so that I can use cookies.