This puzzle shows off how a firewall works. You can ping out of a firewall, but not ping the computers behind it. To "solve" this, ping the lone computer from both subnets, and try to ping both subnets from the lone pc. Firewall Test 1024 1024 100 False 2 0 158 full firewall0 100 100 410,410 firewall False True 192.168.1.1 0.0.0.0 0.0.0.0 gw wan wan0 100 104 firewall0 wan0 wan 104 False wan0 192.168.5.1 255.255.255.0 0.0.0.0 ip lo lo0 100 101 firewall0 lo0 lo 101 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip eth eth0 100 102 firewall0 eth0 eth 102 False eth0 192.168.1.1 255.255.255.0 0.0.0.0 ip eth eth1 100 103 firewall0 eth1 eth 103 False eth1 192.168.2.1 255.255.255.0 0.0.0.0 ip 192.168.5.1 0.0.0.0 0.0.0.0 route 127.0.0.1 0.0.0.0 0.0.0.0 route 192.168.1.1 192.168.1.5 192.168.1.10 route 192.168.2.1 192.168.2.5 192.168.2.10 route net_switch0 100 105 410,190 net_switch False False 0.0.0.0 0.0.0.0 0.0.0.0 gw lo lo0 105 106 net_switch0 lo0 lo 106 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip management_interface management_interface0 105 107 net_switch0 management_interface0 management_interface 107 False management_interface0 0.0.0.0 0.0.0.0 0.0.0.0 ip port port1 105 108 net_switch0 port1 port 108 False port1 0.0.0.0 0.0.0.0 0.0.0.0 ip port port2 105 109 net_switch0 port2 port 109 False port2 0.0.0.0 0.0.0.0 0.0.0.0 ip port port3 105 110 net_switch0 port3 port 110 False port3 0.0.0.0 0.0.0.0 0.0.0.0 ip port port4 105 111 net_switch0 port4 port 111 False port4 0.0.0.0 0.0.0.0 0.0.0.0 ip port port5 105 112 net_switch0 port5 port 112 False port5 0.0.0.0 0.0.0.0 0.0.0.0 ip port port6 105 113 net_switch0 port6 port 113 False port6 0.0.0.0 0.0.0.0 0.0.0.0 ip port port7 105 114 net_switch0 port7 port 114 False port7 0.0.0.0 0.0.0.0 0.0.0.0 ip net_switch1 100 118 230,410 net_switch False False 0.0.0.0 0.0.0.0 0.0.0.0 gw lo lo0 118 119 net_switch1 lo0 lo 119 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip management_interface management_interface0 118 120 net_switch1 management_interface0 management_interface 120 False management_interface0 0.0.0.0 0.0.0.0 0.0.0.0 ip port port1 118 121 net_switch1 port1 port 121 False port1 0.0.0.0 0.0.0.0 0.0.0.0 ip port port2 118 122 net_switch1 port2 port 122 False port2 0.0.0.0 0.0.0.0 0.0.0.0 ip port port3 118 123 net_switch1 port3 port 123 False port3 0.0.0.0 0.0.0.0 0.0.0.0 ip port port4 118 124 net_switch1 port4 port 124 False port4 0.0.0.0 0.0.0.0 0.0.0.0 ip port port5 118 125 net_switch1 port5 port 125 False port5 0.0.0.0 0.0.0.0 0.0.0.0 ip port port6 118 126 net_switch1 port6 port 126 False port6 0.0.0.0 0.0.0.0 0.0.0.0 ip port port7 118 127 net_switch1 port7 port 127 False port7 0.0.0.0 0.0.0.0 0.0.0.0 ip net_switch2 100 139 640,410 net_switch False False 0.0.0.0 0.0.0.0 0.0.0.0 gw lo lo0 139 140 net_switch2 lo0 lo 140 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip management_interface management_interface0 139 141 net_switch2 management_interface0 management_interface 141 False management_interface0 0.0.0.0 0.0.0.0 0.0.0.0 ip port port1 139 142 net_switch2 port1 port 142 False port1 0.0.0.0 0.0.0.0 0.0.0.0 ip port port2 139 143 net_switch2 port2 port 143 False port2 0.0.0.0 0.0.0.0 0.0.0.0 ip port port3 139 144 net_switch2 port3 port 144 False port3 0.0.0.0 0.0.0.0 0.0.0.0 ip port port4 139 145 net_switch2 port4 port 145 False port4 0.0.0.0 0.0.0.0 0.0.0.0 ip port port5 139 146 net_switch2 port5 port 146 False port5 0.0.0.0 0.0.0.0 0.0.0.0 ip port port6 139 147 net_switch2 port6 port 147 False port6 0.0.0.0 0.0.0.0 0.0.0.0 ip port port7 139 148 net_switch2 port7 port 148 False port7 0.0.0.0 0.0.0.0 0.0.0.0 ip pc0 100 115 640,190 pc False False 192.168.5.1 0.0.0.0 0.0.0.0 gw lo lo0 115 116 pc0 lo0 lo 116 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip eth eth0 115 117 pc0 eth0 eth 117 False eth0 192.168.5.2 255.255.255.0 0.0.0.0 ip pc1 100 128 230,600 pc False False 192.168.1.1 0.0.0.0 0.0.0.0 gw lo lo0 128 129 pc1 lo0 lo 129 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip eth eth0 128 130 pc1 eth0 eth 130 False eth0 192.168.1.2 255.255.255.0 0.0.0.0 ip pc2 100 135 90,590 pc False False 0.0.0.0 0.0.0.0 0.0.0.0 gw lo lo0 135 136 pc2 lo0 lo 136 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip eth eth0 135 137 pc2 eth0 eth 137 True eth0 0.0.0.0 0.0.0.0 0.0.0.0 ip pc3 100 149 640,600 pc False False 192.168.2.1 0.0.0.0 0.0.0.0 gw lo lo0 149 150 pc3 lo0 lo 150 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip eth eth0 149 151 pc3 eth0 eth 151 False eth0 192.168.2.2 255.255.255.0 0.0.0.0 ip pc4 100 154 760,600 pc False False 0.0.0.0 0.0.0.0 0.0.0.0 gw lo lo0 154 155 pc4 lo0 lo 155 False lo0 127.0.0.1 255.0.0.0 0.0.0.0 ip eth eth0 154 156 pc4 eth0 eth 156 True eth0 0.0.0.0 0.0.0.0 0.0.0.0 ip 128 130 pc1 eth0 118 121 net_switch1 port1 normal 131 118 122 net_switch1 port2 100 102 firewall0 eth0 normal 132 100 104 firewall0 wan0 105 108 net_switch0 port1 normal 133 105 109 net_switch0 port2 115 117 pc0 eth0 normal 134 135 137 pc2 eth0 118 123 net_switch1 port3 normal 138 100 103 firewall0 eth1 139 142 net_switch2 port1 normal 152 139 143 net_switch2 port2 149 151 pc3 eth0 normal 153 154 156 pc4 eth0 139 144 net_switch2 port3 normal 157 pc0 pc1 FailedPing pc0 pc3 FailedPing pc2 pc0 SuccessfullyPings pc4 pc0 SuccessfullyPings pc4 pc2 SuccessfullyPings Firewall Ping