两个电脑面对面ping 不通，都是用的wifi网络，执行traceroute报错 !H 主机不可达

$ traceroute 192.168.106.81
traceroute to 192.168.106.81 (192.168.106.81), 64 hops max
 1   *  192.168.106.101  53.267ms !H  0.004ms !H

两台电脑重启了后traceroute正常了

$ traceroute 192.168.106.81
traceroute to 192.168.106.81 (192.168.106.81), 64 hops max
 1   192.168.106.81  4.324ms  3.882ms  112.071ms
 

跟踪路由输出中无响应（*）和不可达（！H）主机之间的区别