Review DFS Namespaces Server Requirements

Updated: May 12, 2010

Applies To: Windows Server 2008

A namespace server is a domain controller or member server that hosts a namespace. The number of namespaces that you can host on a server is determined by the operating system running on the namespace server.

The following servers can host multiple domain-based and stand-alone namespaces:

  • Windows Server 2008 Enterprise

  • Windows Server 2008 Datacenter

  • Windows Server 2003 R2 Enterprise Edition

  • Windows Server 2003 R2 Datacenter Edition

  • Windows Server 2003 Enterprise Edition

  • Windows Server 2003 Datacenter Edition

Servers that are running the following operating systems can host multiple domain-based namespaces in addition to a single stand-alone namespace:

  • Windows Server 2008 Standard

  • At least Windows Server 2003 R2 Standard Edition with Service Pack 2

  • At least Windows Server 2003 Standard Edition with Service Pack 2


Windows Server 2003 Web Edition cannot host any namespaces. It can act as a folder target; a maximum of 10 concurrent incoming server message block (SMB) connections are permitted.

The following table describes additional factors to consider when choosing servers to host a namespace.

Guidelines for Servers That Host Namespaces

Server hosting stand-alone namespaces Server hosting domain-based namespaces
  • Only servers running Windows Server 2008 support access-based enumeration for stand-alone or domain-based (Windows Server 2008 mode) namespaces.

  • Must contain an NTFS volume to host the namespace.

  • Can be a member server or domain controller.

  • Can be hosted by a failover cluster to increase the availability of the namespace.

  • Only servers running Windows Server 2008 can host domain-based namespaces in Windows Server 2008 mode.

  • Must contain an NTFS volume to host the namespace.

  • Must be a member server or domain controller in the domain in which the namespace is configured. (This requirement applies to every namespace server that hosts a given domain-based namespace.)

  • Can use multiple namespace servers to increase the availability of the namespace

  • The namespace cannot be a clustered resource in a failover cluster. However, you can locate the namespace on a server that also functions as a node in a failover cluster if you configure the namespace to use only local resources on that server.

Requirements for servers hosting folder targets

Folder targets can be served by any network file system that is accessible by a Universal Naming Convention (UNC) path, such as server message block (SMB), NetWare Core Protocol (NCP) for NetWare, or network file system (NFS) for UNIX. (The client computers must have the appropriate redirector installed to access folder targets.) The UNC path can lead to shared folders in any workgroup, shared folders within the same domain as the namespace, shared folders in trusted domains, and shared folders in trusted forests.


Although computers running Windows Vista® or Windows® 7 can host folder targets, they are generally unsuitable for use as file servers. In addition to their limit of 10 concurrent incoming SMB connections, computers running Windows Vista or Windows 7 by default cannot navigate a DFS namespace to a folder target hosted on the local computer. For example, if a user on a computer running Windows Vista (\client1) attempts to connect to a DFS folder whose folder target is a shared folder located on the same computer (\client1), the connection attempt will fail. This is considered a loopback connection. This behavior is designed to help prevent a rogue namespace server from redirecting a client computer to an administrative share on the client computer (for example \\C$), and then reading or writing files in the shared folder.
To allow a client computer access to folder targets located on the local computer (the default behavior on servers), open Registry Editor, navigate to the following location: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Mup\Parameters, create a DWORD (32-bit) value named EnableDfsLoopbackTargets, and then set the value to 1. After changing the value, restart the computer.
To disable DFS loopback targets (the default behavior on client computers), set the value to 0. After changing the value, restart the computer.

Additional references