首先我们来看一篇文章 “Wake on LAN" (WOL) behavior in Windows 8 and Windows 8.1” ，这是微软官方对WOL在最新的win8和win8.1上的阐释，内容：
- The "Wake on LAN" (WOL) feature wakes a computer from a low-power state when a network adapter detects a WOL event.
- Typically, such an event is a specially constructed Ethernet packet. The default behavior in response to WOL events has changed from Windows 7 to Windows 8.
- Windows 7
- In Windows 7, the default shutdown operation puts the system into the classic shutdown state (S5), and all devices are put into the lowest power state (D3).
- WOL from S5 is not officially supported in Windows 7. However, some network adapters can be left armed for waking if enough residual power is available.
- Therefore, waking from S5 is possible on some systems if enough residual power is supplied to the network adapter even though the system is in the S5 state and devices are in D3.
- Windows 8 and Windows 8.1
- In Windows 8 and Windows 8.1, the default shutdown behavior puts the system into the hybrid shutdown state (S4), and all devices are put into D3. WOL from S4 or S5 is unsupported.
- Network adapters are explicitly not armed for WOL in either S5 or S4 cases because users expect zero power consumption and battery drain in the shutdown state.
- This behavior removes the possibility of invalid wake-ups when an explicit shutdown is requested. Therefore, WOL is supported only from sleep (S3) or hibernation (S4) states in Windows 8 and 8.1.
首先呢，说明了WOL的工作原理，这是对于计算机在低功耗模式下的一种唤醒，它是通过网卡检测WOL事件完成的，而WOL事件呢就是那个以FFFFFF开头的udp数据包啦，感兴趣的朋友可以看下，这个udp包属于ARP的，抓包看下内容就一目了然了。win8.1的快速关机时将计算机关闭到hybrid shutdown state (S4)而不是 classic shutdown state (S5)，而且在S4 S5状态下网卡都是不工作的因为这两种模式都几乎是无功耗的。
- In Windows 8 and 8.1, hybrid shutdown (S4) stops user sessions but lets the contents of kernel sessions be written to the hard disk. This enables faster startups.
- To disable the S4 state in Windows 8 and 8.1, follow these steps.
- Note We do not recommend that you disable the hybrid shutdown (S4) state.
- In Control Panel, open the Power Options item.
- Click the Choose what the power buttons do link.
- Clear the Turn on fast startup (recommended) check box.
- Click Save Settings.