Disabling Strict Name Checking on Windows 2008 R2 Server
You encounter below error when you try to access a folder shared on Windows 2008 R2 Server via DNS CNAME (like \<CNAME><share> path)
“You are not connected because a duplicate name exists on the network”
and this happens for all cnames on that server. In such a case you may need to apply the fix in MSFT article to make it work.
Technical details:
The same Microsoft article Connecting to SMB share on a Windows 2000-based computer or a Windows Server 2003-based computer may not work with an alias name, is updated with notes for W2K8 R2 and Win 7 platforms as shown below:
The registry key that is mentioned in the “Resolution” section 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 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 in the “Resolution” section on Windows Server 2008, Windows Server 2008 R2, Windows Vista, or Windows 7.
So, possibly either of your Windows 7 clients or Windows 2008 R2 servers are still using SMB 1.0 version thus causing such a file share access errors and apparently still requiring the registry work around to resolving them. You need to ensure or set up your infrastructure to configure the SMB 2.0 as the default file sharing communication protocol.
SMB 2.0 was redesigned for networking environments that include wireless, possible high loss, time-outs, high latency, and other networks. SMB 2.0 also meets the needs of the next generation of file servers that include Encrypting File System (EFS) over the wire and Offline Files and Folders improvements.
