How to Delete and Recreate the _msdcs DNS zone on a Windows DNS Server

解决方法来自：http://www.dell.com/support/article/us/en/19/SLN155826/en

In an Active Directory (AD) domain, the _msdcs DNS zone stores several types of resource records pertaining to domain controllers (DCs). If this zone is not present or not functioning properly, domain members may not be able to locate a DC and thus may not be able to access resources in the domain. When troubleshooting an issue involving the _msdcs zone, if all other steps fail to resolve the problem, it may be necessary to delete and recreate the zone. This article provides the procedure for doing so.

Note: If the _msdcs zone appears to be missing entirely, it may instead exist as a folder inside the domain forward lookup zone. Verify whether this is the case before proceeding.

Before deleting the zone, back up the existing data:

• For non-AD-integrated zones, a backup can be made by simply copying the contents of the %windir%\System32\dns folder.

• AD-integrated zones are stored in Active Directory. To back them up, back up the system state of a DC that is also a DNS server.

1：恢复被删除的_msdcs.51xueit.info区域的方法

Once a backup has been made, perform the following steps to delete and recreate the _msdcs zone:

1. Open the DNS console (Start -> All Programs -> Administrative Tools-> DNS).

2. Right-click the _msdcs zone or folder and select Delete. Confirm that you wish to delete the zone or folder.

3. If _msdcs existed as a separate zone, right-click Forward Lookup Zones in the left pane and select New Zone. Use the wizard to create the zone. Name the new zone _msdcs.domain, where domain is the full DNS name of your AD domain. For example, if your domain is named mydomain.local, name the new zone _msdcs.mydomain.local.
   If _msdcs existed as a folder inside the domain forward lookup zone, right-click that zone in the left pane and select New Domain. Name the new domain (folder) _msdcs and click OK.

4. Right-click your server in the left pane and select All Tasks -> Restart to restart the DNS Server service.

5. Open a command prompt and run the following commands:
      ipconfig /flushdns
      ipconfig /registerdns
      net stop netlogon
      net start netlogon

6. Wait a few minutes and refresh the DNS console. The new _msdcs zone or folder should now be populated with a number of records and subfolders.

7. If there are multiple DCs in the domain, perform step 5 on each one to register that DC's resource records in the new zone or folder.

For general steps for troubleshooting DNS issues, refer to this TechNet article.

Quick Tips content is self-published by the Dell Support Professionals who resolve issues daily. In order to achieve a speedy publication, Quick Tips may represent only partial solutions or work-arounds that are still in development or pending further proof of successfully resolving an issue. As such Quick Tips have not been reviewed, validated or approved by Dell and should be used with appropriate caution. Dell shall not be liable for any loss, including but not limited to loss of data, loss of profit or loss of revenue, which customers may incur by following any procedure or advice set out in the Quick Tips.

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2：解决_msdcs.51xueit.info区域缺少某些记录

来自：https://social.technet.microsoft.com/Forums/windowsserver/en-us/3573db98-7da4-493d-9406-924e2f942e82/how-to-fix-missing-cname-record-guidmsdcsmydomain?forum=winserverDS

You can restart the netlogon service & it should refresh all the records in dns & create the missing records like cname, srv etc.

You can recreate the missing cname manually & GUID of DC can be used from AD sites & service, click the site, server,server name, right click Ntds settings you will see the GUID name & create it.

If, you have two _msdcs folder listed in dns, delete the greyed one & even if you delete both & restarting netlogon & dns server service will recreate _msdcs folder followed by dcdiag /fix & netdiag /fix.

You can also use ipconfig /flushdns & ipconfig /registerdns

Post the result of dcdiag /test:dns

Below is the long thread & you can refer.

http://social.technet.microsoft.com/Forums/en/winserverDS/thread/8c192f67-b9d9-4bae-80a4-b3e9eabd3612