当你使用的是以下图中的命令时：出现以上的报错，那就是因为tomcat这个容器中没有ping命令，需要单独下载。
先进入容器：docker exec -it 容器名或容器id /bin/bash
进入容器执行，apt-get install net-tools 命令
再执行，apt-get install iputils-ping 命令
容器不停止退出：Ctrl+P+Q
然后再次执行 docker exec -it 容器名或容器id ping [ip地址]
[root@fanguoan /]# docker exec -it tomcat-net-01 ping 192.168.0.3
PING 192.168.0.3 (192.168.0.3) 56(84) bytes of data.
64 bytes from 192.168.0.3: icmp_seq=1 ttl=64 time=0.110 ms
64 bytes from 192.168.0.3: icmp_seq=2 ttl=64 time=0.083 ms
64 bytes from 192.168.0.3: icmp_seq=3 ttl=64 time=0.082 ms
64 bytes from 192.168.0.3: icmp_seq=4 ttl=64 time=0.075 ms
64 bytes from 192.168.0.3: icmp_seq=5 ttl=64 time=0.083 ms
64 bytes from 192.168.0.3: icmp_seq=6 ttl=64 time=0.084 ms
64 bytes from 192.168.0.3: icmp_seq=7 ttl=64 time=0.083 ms
标签：shorthand,seq,unknown,0.3,bytes,192.168,64,ttl,docker From： https://www.cnblogs.com/fanguoan/p/17415065.html