Author: Chuck Arconi

Connecting to SMB share on a Windows 2000-based computer or a Windows Server 2003-based computer may not work with an alias name.

 

This KB article title is a little deceiving because there are several other instances where this multiple CNAME problem occurs.

http://support.microsoft.com/kb/281308

Microsoft says:

"When a client computer connects to a Microsoft Windows 2000-based computer or a Microsoft Windows Server 2003-based computer by using an alias name, the client may receive the following error message:
System error 52 has occurred.
A duplicate name exists on the network.

This problem can occur when you try to connect to the server by using a CNAME alias that is created in the DNS zone. For example, this problem may occur with a command similar to the following sample command
net view \\alias.domain name.com where alias is a CNAME record that is created for the server in the domain name.com zone. The server is not "listening" on the alias, and therefore is not accepting connections to that name. "

I experienced this recently when after creating a share on a server for a specific application we also created a CNAME pointing to that share so users could easily connect to it by the applications name. This made it easy for them to remember how to get there. After creating the CNAME we could not connect to it and we received the error - "System error 52 has occurred. A duplicate name exists on the network."

We located this article and made the registry change and it worked fine from then on. But my issue wasn't making the registry change but more in the fact that we would be doing this on a regular basis and the network group was not going to be handling it every time. In fact IT people with much less knowledge around this type of event would be handling it. So I wrote the "StrictCNAME" utility to make it easy to apply the Microsoft fix for an engineer of any level. And also because it made it so much faster for me to do it as well.

Using the tool is easy:

1. Download it here.
2. Run it

 

 

 

 

3. Enter the name of the system or it's IP address.
4. Click "OK"
5. Restart the server.


Here is the Microsoft text dealing with the manual method of fixing it:

"Additionally, to resolve this problem in Windows 2000 Server you must complete all of the following steps:

1. Create the CNAME record for the file server on the appropriate DNS server, if the CNAME record is not already present.

2. Apply the hotfix to the computer for which the CNAME record was created, not the DNS server. (Unless the DNS server and file server in question is the same computer, and then all of the changes is applied is to that server.) This hotfix affects the LAN Manager Server Service and does not affect DNS functionality.

3. Apply the following registry change to the file server to which you installed the hotfix. To do so:

a. Start Registry Editor (Regedt32.exe).
b. Locate and click the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters
c. On the Edit menu, click Add Value, and then add the following registry value:
Value name: DisableStrictNameChecking
Data type: REG_DWORD
Radix: Decimal
Value: 1
d. Quit Registry Editor.

4. Restart your computer.

Windows Server 2003

To resolve this problem in Windows Server 2003, complete the following steps:

1. Create the CNAME record for the file server on the appropriate DNS server, if the CNAME record is not already present.

2. Apply the following registry change to the file server. To do so, follow these steps:

a. Start Registry Editor (Regedt32.exe).
b. Locate and click the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters
c. On the Edit menu, click Add Value, and then add the following registry value:
Value name: DisableStrictNameChecking
Data type: REG_DWORD
Radix: Decimal
Value: 1
d. Quit Registry Editor.

3. Restart your computer.