Windows NT 4.0 DNR Only "Devolves" Two Domain Suffixes

ID: Q214467

The information in this article applies to:

Microsoft Windows NT Server version 4.0
Microsoft Windows NT Workstation version 4.0

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SYMPTOMS

When a user tries to connect a Windows NT 4.0 client computer to a server that is more than two levels higher in the domain name tree structure, the user may find it necessary to type the full domain name to connect. This is caused by the client computer domain name resolver component (DNR) only "devolving" two domain suffixes.

For instance, if you have a client named

mycomputer.subdomain3.subdomain2.subdomain1.example.microsoft.com

the domain suffix is

subdomain3.subdomain2.subdomain1.example.microsoft.com

If you want to ftp to a server named "myserver.example.microsoft.com," it is necessary to type the full name "myserver.example.microsoft.com." to connect.

If you type only "myserver", the client queries the DNS for the following:

myserver.subdomain3.subdomain2.subdomain1.example.microsoft.com
myserver.subdomain2.subdomain1.example.microsoft.com (one level of devolution)
myserver.subdomain1.example.microsoft.com (two levels of devolution)

CAUSE

The DNR component was designed to only devolve two levels up the domain suffix.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next Windows NT service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp

The English version of this fix should have the following file attributes or later:

Date Time Size File Name Platform

01/07/99 05:01p 42,768 rnr20.dll (x86)

01/07/99 05:11p 43,792 rnr20.dll (Alpha)

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).

With the default settings, it continues to devolve only two levels. However, this hotfix supports the new MaxDomainsSearchListSize registry value to make the devolution behavior configurable:

Registry value:
HKLM\System\CurrentControlSet\Services\Tcpip\Parameters\MaxDomainsSearchListSize
Value Type: REG_DWORD
Default: 3 (including the first query with no devolution)
Range:1-12 (decimal)

CAUTION: Setting this value higher than necessary can cause delays in name resolution, as more attempts to locate the name are made.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0.

Additional query words: 4.00

Keywords : kbbug4.00 kbfix4.00
Version : winnt:4.0
Platform : winnt
Issue type : kbbug