ping 百度正常通的情況顯示如下：
[root@ecs-a3b8-0206429 ~]# ping baidu.com
PING baidu.com (220.181.38.148) 56(84) bytes of data.
64 bytes from 220.181.38.148 (220.181.38.148): icmp_seq=1 ttl=50 time=27.5 ms
64 bytes from 220.181.38.148 (220.181.38.148): icmp_seq=2 ttl=50 time=26.8 ms
64 bytes from 220.181.38.148 (220.181.38.148): icmp_seq=3 ttl=50 time=26.5 ms
64 bytes from 220.181.38.148 (220.181.38.148): icmp_seq=4 ttl=50 time=26.7 ms
64 bytes from 220.181.38.148 (220.181.38.148): icmp_seq=5 ttl=50 time=26.5 ms
^C
--- baidu.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4006ms
rtt min/avg/max/mdev = 26.554/26.857/27.517/0.378 ms
最近搭了一套系統，網絡鏈路比較負載，ping外網比如baidu時報錯：Time to live exceeded
[root@ecs-a3b8-0206438 ~]# ping baidu.com
PING baidu.com (220.181.38.148) 56(84) bytes of data.
From 192.168.0.56 (192.168.0.56) icmp_seq=1 Time to live exceeded
From 192.168.0.56 (192.168.0.56) icmp_seq=2 Time to live exceeded
From 192.168.0.56 (192.168.0.56) icmp_seq=3 Time to live exceeded
From 192.168.0.56 (192.168.0.56) icmp_seq=4 Time to live exceeded
^C
--- baidu.com ping statistics ---
4 packets transmitted, 0 received, +4 errors, 100% packet loss, time 3004ms
查看dns配置：
[root@ecs-a3b8-0206438 ~]# cat /etc/resolv.conf
# Generated by NetworkManager
search openstacklocal novalocal
nameserver 100.125.108.250
nameserver 202.98.192.67
[root@ecs-a3b8-0206438 ~]#