Managing whether the CIFS server automatically advertises DFS capabilities

Clustered Data ONTAP uses DFS referrals in the implementation of symbolic links for SMB access. You should keep the following in mind when deciding whether to enable or disable this option:

• If automatic DFS advertisements are enabled, the CIFS server always advertises DFS capabilities to SMB 2.x and SMB 3.0 clients connecting to a share regardless of whether symbolic link access for CIFS is enabled on that share.

  This is the default setting.

• If automatic DFS advertisements are disabled, the CIFS server advertises DFS capabilities to SMB 2.x and SMB 3.0 clients only when the clients are connecting to shares where symbolic link access is enabled (either read-write or read-only access) and does not advertise DFS capabilities to clients if they are connecting to shares where symbolic link access is disabled.

Clients that are connected to shares where symbolic link access is disabled might not be able to access these shares after the CIFS server option is disabled. This is because the clients have cached information that the CIFS server is DFS capable, and it is no longer advertising that it is. This causes reconnections to SMB shares to fail. There are two ways to manage this:

• Before disabling the option, you can change the share setting on all shares to allow either read-write or read-only access.
• If it is not possible to change the settings for shares where symbolic link access is disabled, after the option is disabled, you can reboot any affected clients that are connected to these shares, thus clearing the cached information.