> If we have two network interfaces configured on a NetBSD system,
> How will we select that a particular operation on network has to be
> performed through a desired interface.

> Suppose if I have to do ftp or ping thru a desired interface how will
> I select the interface to be used.

Normally this is controlled by the routing table - packets will leave
via the interface indicated by the route selected for the destination
address.

Some programs, particularly those intended for network debugging, have
options that can control this in more detail (for example, ping's -r
can sometimes do what you want).  Check the individual program's
manpages for details.

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