It's just a single router provided by my ISP.
pass-through, PPPoE filtering of on-PPPoE packets between WAN and LAN. Fortunately, most routers do not use symmetric NAT.
Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol for encapsulating PPP frames inside Ethernet frames and has ethertype 0x8863 and 0x8864, meaning that it cannot be offloaded.
