KDC does not allow clients to specify an etype in Windows Server 2003

The Microsoft Windows Server 2003 Key Distribution Center (KDC) uses the strongest encryption type (etype) available to encrypt service tickets. If a client requests etype DES-CBC-CRC, the KDC encrypts tickets with RC4_HMAC_NT. If the client does not understand this etype, the service ticket is unusable.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

See the "More Information" section in this article.

Restart requirement

You do not have to restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

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

By default, the new logic that is introduced in this hotfix is disabled. To enable the new logic, follow these steps.

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.

1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Kdc
3. Right-click Kdc, point to New, and then click DWORD Value.
4. Type KdcUseRequestedEtypesForTickets as the New Value.
5. Right-click KdcUseRequestedEtypesForTickets, and then click Modify.
   
   Important To enable a client to specify an etype, set the KdcUseRequestedEtypesForTickets registry value to 1. If you remove the KdcUseRequestedEtypesForTickets registry value, the KDC will use the default behavior.
6. Click OK, and then quit Registry Editor.
7. Restart the Key Distribution Center service.
   
   Note This registry change does not take effect until you restart the Key Distribution Center service.

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

If you can, upgrade or modify the client to support DES-CBC-MD5. Alternatively, use the Windows 2000 KDC for clients that must specify the encryption type for service tickets.