These are the 2 scenarios:
On the left size, the case that ZeroShell fail to support with Netbalance. My guess is that SZ expect Ethernet adapters to be specified to netbalance with a gateway, and will not pick the DHCP assigned one. The routing case for this case is:
Also, for this scenario, the Dynamic DNS works only for the PPPoE interface, as it will not work for 2 interfaces nor for DHCP based interfaces.
On the right size of the first image is the scenario that I had to resort to. I’ve added an intermediate router to make the ethernet interface for ZS a fixed IP, as well as to handle the Dynamic DNS for the cable modem side.
The routing table for this case is: