You can specify the preferred storage system network interface to be used when establishing an NDMP data connection to another storage system.
By default, an NDMP data connection uses the same network interface as the NDMP control connection established by the NDMP backup application. However, to establish a data connection between NDMP-enabled storage systems over an alternate network, you need to specify the storage system’s interface through which the alternate network will be accessed.
For example, a UNIX or NT resident NDMP backup application and multiple storage systems can be interconnected through a corporate network. The same storage systems can also be interconnected through an isolated private network. To minimize load on the corporate network, the options ndmpd.preferred_interface command can be used to direct all NDMP data connections over the isolated private network.