>It's hard to imagine a network interface (except ppp0) without a 48-bit MAC address? Not super common but there's Infiniband. Latter versions supported encaps

>It's hard to imagine a network interface (except ppp0) without a 48-bit MAC address? Not super common but there's Infiniband. Latter versions supported encapsulating ethernet frames (Ethernet over InfiniBand) but not all hardware supports it. Otherwise it's straight IP over IB. There must be other niche networking technology that does IP without Ethernet.