Ubuntu14.04修改配置，重启网卡没有生效，出现如下问题：
service networking restart //重启网络服务 stop: Job failed while stopping start: Job is already running: networking
tail -f /var/log/upstart/networking.log //查看错误日志 Stopping or restarting the networking job is not supported. Use ifdown & ifup to reconfigure desired interface.
从以上日志内容可以看出，传统的service重启和停止网络已经不再支持了，需要通过使用ifdown & ifup来实现相应的操作。
- 重启指定网卡
ifdown eth0 && ifup eth0
- 重启除lo网卡的所有网卡
ifdown --exclude=lo -a && sudo ifup --exclude=lo -a
- 配置桥接
# apt-get install bridge-utils # cat /etc/network/interfaces auto lo iface lo inet loopback auto eth0 iface eth0 inet manual auto br0 iface br0 inet static address 192.168.0.10 netmask 255.255.255.0 gateway 192.168.0.1 bridge_ports eth0 bridge_stp off bridge_fd 0 bridge_maxwait 0 dns-nameservers 192.168.0.1 # ifup br0 # brctl show bridge name bridge id STP enabled interfaces br0 8000.02000a0080e1 no eth0