default gateway: 172.17.2.52
                                     |
                                     |      GigEth1       GigEth2
[ DNS / DHCP server: 172.17.2.53 ]---+-----------[ MAP-BR ] ------+
                                                                  |
                                                                  |
                                                                  |
                                                                  |
                                                                  |
                                LAN            WAN  pppoe         |
[openwrt-build 192.168.1.100] ---- [tl-wdr4300] ------[ agg-rtr ]-+
                                                     GigEth1    GigEth2