How to configure the second network interface on an AnywhereUSB/14

The AnywhereUSB/14 has two Ethernet ports, as a form of redundancy for the attached switch(es), but only one actual network interface (NIC).  Because the unit does not have a second NIC, it's only possible to configure one IP address for the one NIC, not two IP addresses.

Related KB article:
https://www.digi.com/support/knowledge-base/anywhereusb-14-redundancy-features-in-detail