Distributed File System

The Distributed File System (Dfs) service manages logical volumes that are distributed across a local or wide area network, and it is required for the AD DS SYSVOL shared resource. Distributed File System (DFS) is a distributed service that integrates disparate shared files into a single logical namespace.

This namespace is a logical representation of the network storage resources that are available to users on the network. If the Distributed File System service stops, you are unable to access shared files or network data through the logical namespace. To access the data when the service is stopped, you must know the names of all the servers and all the shared files in the namespace, and you must access each of these targets independently. This service is installed as part of the File Services role.

This service is available on a Server Core installation of Windows Server 2008 R2 in addition to the Standard, Enterprise, and Datacenter editions of Windows Server 2008 and Windows Server 2008 R2.

The following table identifies the application protocols, network protocols, and ports that are used by the Distributed File System service:

Application protocol Network protocol Ports
NetBIOS Datagram Service UDP 138
NetBIOS Session Service TCP 139
LDAP Server TCP 389
LDAP Server UDP 389
SMB TCP 445
RPC TCP 135
Randomly allocated high TCP ports TCP Random port number between 1024 and 65535

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