In the ebox interface, set the gateway.
I initially had problems with this. Do it all from the ebox interface and make sure to put in the gateway.
If you try to set up manually, ebox will erase the gateway setting.
For me it goes like this: Assuming one network card.
install ebox
go to network, interfaces, change ip address, and netmask. Do NOT choose external.
Got back to network, add a gateway, then save.
Has worked on about 10 installations.