SendPort DNS Registry Key Does Not Work as Expected

This article was previously published under Q260186
This article has been archived. It is offered "as is" and will no longer be updated.
When you upgrade your Microsoft Windows NT 4.0-based computer that is running Domain Name Service (DNS) to Windows 2000, you may experience name resolution issues.

If you then stop the DNS service and set the following registry key

Value type: REG_DWORD
Value in decimal: 53
as described in the Windows 2000 Resource Kit, you may receive the following error message when you restart the DNS service:
DNS server failed to start with system error 6 - The handle is invalid.
In addition, the following events may be logged in Event Viewer:
Event ID: 407
Source: DNS
Description: DNS server could not bind a datagram (UDP) socket to [IP address of server]. The data is the error.

Event ID: 408
Source: DNS
Description: DNS Server could not open socket for address [IP address ofserver]. Verify that this is a valid IP address on this machine. If it is NOT valid use the Interfaces dialog under Server Properties in the DNS Manager to remove it from the list of IP interfaces. Then stop and restart the DNS server. (If this was the only IP interface on this machine and the DNS server may not have started as a result of this error. In that case remove the DNS\Parmeters\ListenAddress value in the services section of the registry and restart.) If this is a valid IP address for this machine, make sure that no other application (e.g. another DNS server) is running that would attempt to use the DNS port.
NOTE: The DNS server starts as expected if you configure the SendPort registry key to a value other than 53.
This problem occurs because of a change in DNS behavior in Windows 2000.
To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
260910 How to Obtain the Latest Windows 2000 Service Pack
The English-language version of this fix should have the following file attributes or later:
   Date        Time    Version         Size    File name  Platform   ---------------------------------------------------------------   06/13/2000  03:47p  5.0.2195.2096   321,296 Dns.exe    Intel				

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 2.
Windows 2000 DNS uses ephemeral ports as the source port in an iterative query from a Windows 2000 DNS server to a root server, and Windows NT 4.0 and BIND implementations of DNS use User Datagram Protocol (UDP) port 53. Because of this, you need to leave all ephemeral ports open when you configure a firewall or router Access Control List (ACL).

For additional information about how to install Windows 2000 and Windows 2000 hotfixes at the same time, click the article number below to view the article in the Microsoft Knowledge Base:
249149 Installing Microsoft Windows 2000 and Windows 2000 Hotfixes

Article ID: 260186 - Last Review: 12/05/2015 19:48:27 - Revision: 2.4

Microsoft Windows 2000 Server, Microsoft Windows 2000 Advanced Server

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