A. The MUP (Multiple UNC Provider) first establishes whether Distributed File System (Dfs) is in use and passes the request to DFS.

The delays come from two locations:

  1. The attempt to access the resource through DFS
  2. The MUP must wait and accept all responses from all redirectors before completing the request. Therefore, even if a resource is readily available and accessible over one redirector, the request must still be made over the other installed redirectors before the request completes.

Depending on the number of redirectors, protocols, and timer configurations for connectivity, these delays can exceed 13 seconds for each initial connection.

Service Pack 4 for Windows NT 4.0 has introduced an updated MUP.SYS giving better performance and a new registry entry which may speed up the initial connect to non-Windows UNC resources, DisableDFS. Perform the following change on each client:

  1. Start the registry editor (regedit.exe)
  2. Move to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Mup
  3. From the Edit menu select New - DWORD value
  4. Enter a name of 'DisableDFS' (don't enter the quotes) and press enter
  5. Double click the new value and set to 1. Click OK
  6. Close the registry editor
  7. Reboot the machine

Setting the DisableDFS value to 0 or deleting will set the machine back to its old behaviour.

If you have the Novell IntranetWare client also installed you must also perform the following before rebooting:

  1. Start the registry editor (regedit.exe)
  2. Move to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetwareWorkstation\NetworkProvider
  3. Double click DeviceName and change from '\Device\NetwareWorkstation' to '\Device\NetwareRedirector'. Click OK
  4. Close the registry editor

Knowledge base article Q171386 at http://support.microsoft.com/support/kb/articles/q171/3/86.asp has more information on this.