Linux 安裝mtr

1.yum install mtr -y

報錯：No more mirrors to try.

 

 2.yum clean all

　yum makecache

　yum -y update

 

 3.重新安裝 

　yum install mtr -y

 4.查看是否安裝成功

　 yum list installed |grep mtr

 疑問：重新安裝依然報錯：No more mirrors to try，但是查看卻有？