beacuse the mac address of net adapter is changed,so you need modifiy it,the easy way is
<font face="Courier New"><span>sudo</span> <span>rm</span><span> </span><span>/</span><span>etc</span><span>/</span><span>udev</span><span>/</span><span>rules.d</span><span>/</span><span>70</span><span>-persistent-net.rules</span></font><span></span><span> sudo</span><span> /</span><span>etc</span><span>/</span><span>init.d</span><span>/</span><span>networking restart</span> reference: http://blog.sina.com.cn/s/blog_4b33b7380100f64s.html