当我这样做时，ping google.com我得到ping: unknown host google.com
但是ping 173.194.67.138我什么时候得到这个：
PING 173.194.67.138 (173.194.67.138) 56(84) bytes of data.
64 bytes from 173.194.67.138: icmp_seq=1 ttl=48 time=5.33 ms
64 bytes from 173.194.67.138: icmp_seq=2 ttl=48 time=5.40 ms
所以在尝试解析 DNS 时肯定有错误，有什么我可以做的吗？
这是来自我的系统日志：
Aug 14 19:55:15 localhost ntpd[1184]: ntpd 4.2.6p5@1.2349-o Mon Apr 13 13:39:46 UTC 2015 (1)
Aug 14 19:55:15 localhost ntpd[1185]: proto: precision = 0.102 usec
Aug 14 19:55:15 localhost ntpd[1185]: ntp_io: estimated max descriptors: 1024, initial socket boundary: 16
Aug 14 19:55:15 …