运行以下命令，删除旧的网络配置，重新让networkmanager自动配置即可
sudo service network-manager stop
sudo rm /var/lib/NetworkManager/NetworkManager.state
sudo service network-manager start
详情参考：http://joseph.yy.blog.163.com/blog/static/50973959201191210131545/
原文：http://www.cnblogs.com/zhp-king/p/7117889.html