Using prepaid 4G service for backup internet?
Is it possible to use a 4G carrier as a backup internet connection? Is there a prepaid carrier in the US that sells a dongle or device that is compatible with pfSense?
Yes and Yes.
On Verizon's website, I see 3 USB modems listed:
Verizon 551L, Pantech UML290, and Verizon UML295 (out of stock).
I see the UML290 listed as working on the Known_Working_3G-4G_Modems page, but, going off-topic, I don't see that it's eligible for any prepaid plans on Verizon's confusing website.
Are there any Verizon-based budget carriers this would work with?
Apologies for being off-topic.
Is it possible to do this with tiered gateways and 'dial-on'demand'?
My 3G provider charges me a fixed daily fee for each day the link shows as active. It's the same fee for 1 byte or 1 gigabyte of traffic. To minimize charges I don't want the 2nd tier gateway to go active unless the 1st tier drops out altogether.
My initial thought was that I would need a router (OpenWRT) for the 2nd tier gateway. It would show pfSense it's ethernet interface as up and I could control dial-on-demand at the router. The 2nd tier gateway router can be an OpenWRT device or similar, or another pfSense box. For my application I would have to locate the radio antenna almost 100m away at the top of the hill in order to get a signal. A 12v battery powered, solar charged 'base station' connected by a CAT5 cable in a duct back to my comms cabinet. In my rural location 4G is a long way off geographically and on timeline. 3G is sporadic, GPRS being probably the reality most of the time.
You can put the 3/4G device on the lowest tier of a failover gateway group and it won't be used until the other gateway(s) go down. However by default pfSense pings evey gateway once a second so you'd have to disable apinger for that gateway. Even then could you guarantee not a single packet would use it? :-\ Not sure.