Thanks, sitloongs and Venn, for your replies! I am trying to accomplish what MartinLangmaid is suggesting on the Pepwave forum here. This is a screenshot of his reply, which concerns a Surf that sits behind another router which is behind an ISP modem or gateway.
My Surf sits behind my ISPs gateway, and I would like to set the Surf’s firewall to limit all incoming traffic to that which comes through my ISP. A problem is that the ISP assigns dynamic IPs to residential customers. Is there a way to accomplish what MartinLangmaid is suggesting for a dynamic IP? Thanks for your advice!