FIX: Slow Responses and Failures When You Use Server Publishing UDP Protocols

When you use Server Publishing UDP Protocols (for example, DNS Query), you may notice a variety of problems:

• A lot of performance problems.
• You cannot connect to the published DNS server externally.
• The server may also stop responding after some days and the only resolution is to restart the computer.

Typically, these problems occur when you use Server Publishing DNS Query protocols where requests to the published DNS server from external sources receive a response only after a long delay, or not at all (the request does not succeed).

Note You do not experience these symptoms when you use Server Publishing TCP protocols through ISA Server (for example, DNS Zone Transfer).

These problems occur only if the Site and Content Rules match one of the following configurations:

• There is at least one Deny Site and Content Rule configured that includes FQDN in Destination Sets.
• There is no Allow All rule configured, and at least one of the Allow Site and Content Rules includes FQDN in Destination Sets.

Make sure that no FQDN are included in Site and Content Rules on the computer running ISA Server where you have configured the UDP Server Publishing Rule.

To resolve this problem, obtain the Update Rollup for ISA Server Services. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix Information

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk. Because the hotfix implements the use of Negative DNS Cache, you must set the appropriate TTL value in the registry. To do this, follow these steps:

1. Start Registry Editor.
2. Locate and then click the following registry key:
   System\CurrentControlSet\Services\FwSrv\Parameters
3. Create a new DWORD value named NegativeDnsCacheTTL. Microsoft recommends that you give this data a value of 300 (5 minutes).
   
   Important If this value is missing, or set to 0, ISA Server will not use negative caching and the fix will not work correctly.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.