問題：正在使用的Linux系統突然有一天不能解析域名gus.xxxxxxxx.com?

　　# ping us.xxxxxxxx.com

　　ping: unknown host us-xxxxxxxx.com

解決方法：

1、查看/etc/hosts　

# cat /etc/hosts
　127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
　::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
　192.168.1.3 us.xxxxxxxx.com

2、查看/etc/host.conf

# cat /etc/host.conf
　order hosts, bind
　multi on

3、查看/etc/resolv.conf

# cat /etc/resolv.conf
 search localdomain
　#nameserver 8.8.4.4
　nameserver 8.8.8.8

初始使用的是 “nameserver 8.8.4.4”，導致域名解析錯誤，后來改為"nameserver 8.8.8.8"就可以正常解析了

#ping us.xxxxxxxx.com
　　PING gus.xxxxxxxx.com (192.168.1.3) 56(84) bytes of data.
　　64 bytes from ec192-168-1-3.ap-northeast-2.compute.amazonaws.com (192.168.1.3): icmp_seq=1 ttl=39 time=458 ms