ISA Server 2000 unexpectedly allows NetBIOS traffic from all external IP addresses after you configure a packet filter to allow "NetBIOS (all)" traffic from a specific external IP address

Assume the following scenario. In Microsoft Internet Security and Acceleration (ISA) Server 2000, you create a packet filter that has the following configuration.

Setting	Value
Name	name
Filter mode	Allow packet transmission
Filter type	NetBIOS (all)
Local computer	Default IP addresses for each external interface or IP address of an external interface
Remote computer	Only this remote computer::IP address

When you enable this packet filter, ISA Server allows NetBIOS traffic from the remote IP address as you expect. However, ISA Server also allows NetBIOS traffic from all other remote IP addresses.

You expect NetBIOS traffic to be blocked from all IP addresses except from the IP address that you specified in the IP packet filter.

To resolve this issue, download and install the MS05-034 security update. For more information about this update, visit the following Microsoft Web site:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information, click the following article number to view the article in the Microsoft Knowledge Base: