According to this Microsoft article 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.
To resolve this problem in Windows Server 2003, follow these 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:
1. Start Registry Editor (Regedt32.exe).
2. Locate and click the following key in the registry:
3. On the Edit menu, click Add Value, and then add the following registry value:
Value name: DisableStrictNameChecking
Data type: REG_DWORD
4. Quit Registry Editor.
3. Restart your computer.
You may also have to set the SPN (Service Principal Name) for the Alias Name:
setspn -a host/aliasname targetserver
setspn -a host/aliasname.contoso.com targetserver
The registry key that is mentioned is applicable only to SMB 1.0. To communicate over the SMB2.0 protocol, or CIFS (Common Internet File System), you do not have to set the registry key. SMB 2.0 allows for the functionality described in this article to work by default without additional configuration. Computers that run Windows Server 2008, Windows Server 2008 R2, Windows Vista, and Windows 7 support both SMB 1.0 and SMB 2.0. Windows includes an SMB client component (Client for Microsoft Windows) and an SMB server component (File and Printer Sharing for Microsoft Windows). By default, SMB 2.0 is the file sharing protocol that is used when both client and server support it.
The SMB protocol revision to be used for file operations is decided during the negotiation phase. A Windows Vista or later client advertises to the server that it understands the new SMB 2.0 protocol. If the server understands SMB 2.0, SMB 2.0 is used for communication. Otherwise, the client and server use SMB 1.0. If SMB 1.0 is expected to be used, you can set the registry key that is mentioned above on Windows Server 2008, Windows Server 2008 R2, Windows Vista, or Windows 7.