This alert can be indicative of a possible denial of service attack.
This can be caused by a denial of service attack or a significantly overloaded NLB cluster.
Analyze the threats against the Network Load Balancing (NLB) cluster, including potential denial-of-service attacks, and then take the appropriate measures. For more information about security, see Security and Protection.
If it is not an attack, the NLB cluster may be overloaded. To distribute the cluster traffic load over more hosts, you can add more hosts to the NLB cluster.
When you are using 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 add a host to the NLB cluster:
Click Start, click Administrative Tools, and then click Network Load Balancing Manager. You can also open NLB Manager by typing Nlbmgr at a command prompt.
Right-click the cluster where you want to add the host and choose Add Host To Cluster. If NLB Manager does not list the cluster, connect to the cluster.
Type the host's name and click Connect. The network adapters that are available on the host will be listed at the bottom of the dialog box.
Click the network adapter that you want to use for NLB, and then click Next. The IP address configured on this network adapter will be the dedicated IP address for this host.
Configure the remaining host parameters as appropriate, and then click Finish.