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How to control automatic DFS advertisements in clustered Data ONTAP with a CIFS server option

A CIFS server option has been added that controls how DFS capabilities are advertised to SMB clients when connecting to shares. Because clustered Data ONTAP uses DFS referrals when clients access symbolic links over SMB, you should be aware of what the impact is when disabling or enabling this option.

In clustered Data ONTAP 8.2 through 8.2.2, the CIFS servers on Storage Virtual Machines (SVMs) always advertise to SMB clients that they are DFS capable. However, even though the CIFS servers always advertise that they are DFS capable, symbolic link access for SMB is managed on a share-by-share basis by setting a share parameter. By using the share parameter, you can set symbolic link access for SMB to one of three access levels:

Starting with Data ONTAP 8.2.3 in the 8.2 release family and with Data ONTAP 8.3 and later, a CIFS server option determines whether the CIFS servers automatically advertise that they are DFS capable to SMB clients. By default, this option is enabled and the CIFS server always advertises that it is DFS capable to SMB clients (even when connecting to shares where access to symbolic links is disabled). If you want the CIFS server to advertise that it is DFS capable to clients only when they are connecting to shares where access to symbolic links is enabled, you can disable this option.

You should be aware of what happens when this option is disabled:

These changes do not apply to SMB 1.0 connections.