Will Viva work with any router or modem?

The Viva gateway requires an available standard ethernet port on the router. When connecting the gateway, make sure that the port does not serve a special purpose, for instance "Television" or "IP telephony". 

The ports needed are 443/TCP outgoing, which is used by SSL/TLS (i.e. internet traffic), as well as 8883 which is registered for MQTT over TLS. 

Note: Even though typically these ports are open, Viva has received information some TP-Link routers have 8883 closed.