呵呵 一点儿小技巧 不懂原理的可以私聊本人。

   ping www.baidu.com

   ping: unknown host www.baidu.com

     vim /etc/resolv.conf 

     nameserver 8.8.8.8

 ping 8.8.8.8

* 网络不可达

 ifconfig eth0 192.168.1.235  up

  ping 8.8.8.8

  ifconfig eth0 192.168.1.235 netmask 255.255.255.0  up

  ping 8.8.8.8

 route add default gw 192.168.1.1

  ping 8.8.8.8

  ping baidu.com

PING www.a.shifen.com (61.135.169.121) 56(84) bytes of data.

64 bytes from 61.135.169.121: icmp_seq=1 ttl=56 time=3.90 ms

64 bytes from 61.135.169.121: icmp_seq=2 ttl=56 time=3.05 ms

64 bytes from 61.135.169.121: icmp_seq=3 ttl=56 time=3.93 ms

64 bytes from 61.135.169.121: icmp_seq=4 ttl=56 time=48.4 ms

64 bytes from 61.135.169.121: icmp_seq=5 ttl=56 time=19.5 ms

64 bytes from 61.135.169.121: icmp_seq=6 ttl=56 time=5.08 ms

64 bytes from 61.135.169.121: icmp_seq=7 ttl=56 time=5.55 ms

64 bytes from 61.135.169.121: icmp_seq=8 ttl=56 time=6.04 ms

64 bytes from 61.135.169.121: icmp_seq=9 ttl=56 time=2.42 ms

64 bytes from 61.135.169.121: icmp_seq=10 ttl=56 time=2.12 ms