不能ping我的docker容器外的主机
嗨，我已经安装并启动了docker集装箱。 当我访问这个容器，并做ifconfig时，这是我得到：
eth0 Link encap:Ethernet HWaddr 02:42:0a:32:00:02 inet addr:10.50.0.2 Bcast:0.0.0.0 Mask:255.255.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:387 errors:0 dropped:0 overruns:0 frame:0 TX packets:18 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:73801 (73.8 KB) TX bytes:1572 (1.5 KB) eth0:1 Link encap:Ethernet HWaddr 02:42:0a:32:00:02 inet addr:10.50.1.1 Bcast:10.50.255.255 Mask:255.255.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 eth0:2 Link encap:Ethernet HWaddr 02:42:0a:32:00:02 inet addr:10.50.1.2 Bcast:10.50.255.255 Mask:255.255.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 eth0:3 Link encap:Ethernet HWaddr 02:42:0a:32:00:02 inet addr:10.50.1.3 Bcast:10.50.255.255 Mask:255.255.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 我可以完美ping通主机（eth0及其虚拟ip）的地址，
在主机上，这是ifconfig输出
br-dfd292823ec9 Link encap:Ethernet HWaddr 02:42:1b:2b:32:c3 inet addr:10.50.0.1 Bcast:0.0.0.0 Mask:255.255.0.0 inet6 addr: fe80::42:1bff:fe2b:32c3/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:18 errors:0 dropped:0 overruns:0 frame:0 TX packets:320 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1320 (1.3 KB) TX bytes:65375 (65.3 KB) docker0 Link encap:Ethernet HWaddr 02:42:93:9a:5c:ea inet addr:172.17.0.1 Bcast:0.0.0.0 Mask:255.255.0.0 inet6 addr: fe80::42:93ff:fe9a:5cea/64 Scope:Link UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:23 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:2967 (2.9 KB) eth0 Link encap:Ethernet HWaddr ec:b1:d7:56:9d:88 inet addr:10.250.1.49 Bcast:10.250.255.255 Mask:255.255.0.0 inet6 addr: fe80::f784:a7df:5e4e:ce2f/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:270248 errors:0 dropped:0 overruns:0 frame:0 TX packets:113084 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:208274777 (208.2 MB) TX bytes:67211395 (67.2 MB) Interrupt:20 Memory:f7d00000-f7d20000 eth1 Link encap:Ethernet HWaddr 68:05:ca:3e:0c:f3 inet addr:192.168.108.222 Bcast:192.168.109.255 Mask:255.255.254.0 inet6 addr: fe80::8f37:3338:32cf:ba39/64 Scope:Link inet6 addr: 2620:2c:40c0:c00:2d9e:8857:7d24:f4ee/64 Scope:Global UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:94805 errors:0 dropped:1 overruns:0 frame:0 TX packets:19184 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:36493713 (36.4 MB) TX bytes:4842334 (4.8 MB) Interrupt:19 Memory:f7cc0000-f7ce0000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:11023 errors:0 dropped:0 overruns:0 frame:0 TX packets:11023 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1 RX bytes:1730700 (1.7 MB) TX bytes:1730700 (1.7 MB) veth06b2b8e Link encap:Ethernet HWaddr 8e:96:03:60:49:5c inet6 addr: fe80::8c96:3ff:fe60:495c/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:18 errors:0 dropped:0 overruns:0 frame:0 TX packets:392 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1572 (1.5 KB) TX bytes:74749 (74.7 KB)
现在我正试图从与主机相同的networking中的其他机器ping那些容器地址（10.50.0.2,10.50.1.1，…），并添加到它们的路由以使用主机作为gw来访问10.50.0.0/16networking，但我不能ping泊坞箱容器的IP地址。 我使用的是docker 17 ce和ubuntu 16。
所以我find了解决我的问题。 原来，通过做sudo iptables -L -n我发现以下
Chain FORWARD (policy DROP) target prot opt source destination DOCKER-USER all -- 0.0.0.0/0 0.0.0.0/0 DOCKER-ISOLATION all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED DOCKER all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED DOCKER all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
所以FORWARD策略设置为DROP，意味着没有stream量转发到我的docker集装箱，然后做了sudo iptables -P FORWARD ACCEPT并解决了我的问题。