The software answer would be easy: use OpenWRT or any other *BSD based alternative, but what about the hardware? A quick search for WAN interfaces for PCs returned nothing.
Interface most of the time is going to be a dedicated modem for whatever uplink you have, unless you already get Ethernet directly. Depending on your specific situation, you might have to use whatever the ISP gives you and set it to play as dumb as possible.
I would agree that it can be difficult to find quality hardware that supports the open source software stack.
For example, what wireless access points are compatible with an openbsd router/firewall? I’ll admit that my initial searches were short but only finding results about wireless chipsets to use in the router were frustrating (I guess if I wanted to build my own access points that information would be valuable).
Like the ability for the ap to understand how the vlans the router setup work. I’m still quite the network novice but it seems like if I wanted a bsd firewall -> managed switch -> wireless ap I would need to confirm some level of interoperability for decent performance?
That kind of interoperability has nothing to do with the OSes though if you straight-up configure things. VLANs are VLANs, regardless if it's Linux, Windows, BSD, Cisco, ... on the other end of the cable. (And if you expect some kind of automatic configuration sync etc the answer is in reverse "doesn't work unless you buy everything from one vendor", for that part there is little standardization)
That is good to know. Far too many guides I have read for home networks are for single vendor network stacks and despite that never being the case at any of my jobs.
Sorry, used the wrong term. By WAN I meant the broadband telephone line. Modem cards for dial up connections were common back in the day, but since ADSL and beyond I don't recall any commonly available products, USB winmodems aside. VDSL/Fiber capable cards would be very handy to build 100% FOSS broadband routers, but they seem next to unobtanium.
