Posted by: Niko | October 20, 2006

Network share problem when using CNAME alias

Today I found a interesting bug in Windows Lan Manager Server service. We had renamed a server running Windows 2000 Server and created a DNS (CNAME) alias record for it because we wanted to be able to access the server both the new name and the old name. The new name works as it should but when we tried to access the server with its old name we wasn’t able to access.

At the command prompt “net view \\aliasname” -command gave an “System error 52 has occurred. duplicate name exists on the network” error which led me on false path, so first I was browsing the DNS server for false or loose records.

After some googling I found out that it’s a Microsoft bug (KB281308). The server is not listening on the alias name and therefore it is not accepting connections. Luckily there is a fix which solves this issue (see the KB-article for more details):

Note: Operations are made on the file server (not on the DNS server).

1. Apply the latest service pack.
2. Apply the following registry change
2.1 Start registry editor and locate following key:


2.2 Create a new value with following details:

Value name: DisableStrictNameChecking
Data type: REG_DWORD
Radix: Decimal
Value: 1

3. Reboot the server

After this addition in the registry the shares are available also with the old server name. The same fix applies to the Windows 2003 server.




  1. Hi Niko,

    I am a systems admin in San Francisco. Your answer was perfect!

    Just wanted to let you know.

    Thanks again,


  2. FYI, this doesn’t seem to fix the problem in Windows Server 2003 R2. I am not sure why.

  3. Hi,

    Thanks for sharing this. It is perfect!! One thing I have noticed that on some servers, I’m prompted for credentials when accessomg \\alias\share as opposed to \\hostname\share (DNS netmask ordering resolves local server to itself).

    If I type in a valid username and password, it still denies me access.

    Apparently, you can’t access a share using a DNS alias. On one server I have, i am able to access the share using a host name and I am not prompted for any credentials.

    I know DFS is suitable for this, but management is hesitant to go that route, so I need to find something else.

    I’m using Windows Server 2003 R2 SP2. Do you have any ideas?

    Any assistance whatsoever will be greatly appreciated.


  4. Probably long since addressed but may be usefull for someone

    Allowing server machine to use filesharing with itself via the DNS Alias (BackConnectionHostNames)
    This change is necessary for a DNS alias to work with filesharing from a machine to find itself. This creates the Local Security Authority host names that can be referenced in an NTLM authentication request.
    To do this, follow these steps for all the nodes on the client computer:
    1. To the registry subkey
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0, add new Multi-String Value BackConnectionHostNames

    2. In the Value data box, type the CNAME or the DNS alias, that is used for the local shares on the computer, and then click OK.
    •Note: Type each host name on a separate line.

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