Windows 7 / Networking

Using a Network Connection to Wake Up a Sleeping Computer

Most Windows 7 computers are configured to go into sleep mode after a certain amount of idle time. If you're coming to Windows 7 from Windows XP, then sleep mode is the low-power state that Windows 7 uses to replace the confusing standby and hibernate modes from Windows XP. (Standby mode preserved your work and enabled you to restart quickly, but didn't entirely shut off the machine's power; hibernate mode preserved your work and completely shut off the machine, but also took a relatively long time to restart- faster than shutting down your computer entirely, but slower than standby.)

Windows 7's sleep state combines the best of the old standby and hibernate modes:

  • As in standby, you enter sleep mode within just a few seconds.
  • As in both standby and hibernate, sleep mode preserves all your open documents, windows, and programs.
  • As in hibernate, sleep mode shuts down your computer, except it maintains power to the memory chips so that it can preserve the contents of RAM for when you restart.
  • As in standby, you resume from sleep mode within just a few seconds.

To use sleep mode, you have two choices:

  • To launch sleep mode by hand, open the Start menu, click the arrow beside the Shut Down button, and then click Sleep. Windows 7 saves the current state and shuts off the computer in a few seconds.
  • To configure Windows 7 to go into sleep mode automatically, select Start, type sleep, and then click Change When the Computer Sleeps. Use the Put the Computer to Sleep list to select the number of minutes or hours of idle time after which Windows 7 automatically puts the computer to sleep. Click Save Changes.

Having a computer go to sleep when you're not using it is a good idea because it conserves power. However, it can be a pain if you need to access the computer remotely over your network because you have no way to wake up the sleeping computer (which normally requires a physical action such as jiggling the mouse or pressing the computer's power button).

Fortunately, most new NICs support a feature called wake-on-LAN, which enables the NIC to wake up the computer when the NIC receives a special Ethernet packet called a magic packet (usually the hexadecimal constant FF FF FF FF FF FF followed by several repetitions of the computer's MAC address).

For this to work, you must first configure the NIC to handle wake-on-LAN. Here are the steps to follow:

  1. In the Network Connections window, right-click the connection that uses the NIC you want to configure, and then click Properties. The connection's Properties dialog box appears.
  2. In the Networking tab, click Configure to open the NIC's Properties dialog box.
  3. Display the Power Management tab.
  4. Click to activate the Allow This Device to Wake the Computer check box.
  5. Click to activate the Only Allow a Magic packet to Wake the Computer check box.
  6. Click OK.

NOTE If the Allow This Device to Wake the Computer check box is disabled, it probably means your NIC doesn't support wake-on-LAN. However, it may also mean that this support has been disabled. In the NIC's Properties dialog box, display the Advanced tab and look for a property named Wake Up Capabilities. Click this property, and then choose an option in the Value list (such as Magic Packet or On). Click OK to put the new setting into effect, and then retry the steps in this section.

With the computer's NIC configured, you need to download a utility that can send a magic packet to the remote computer whenever you need to wake up the machine. MatCode Software's free Wake-on-LAN utility, available at www.matcode.com/wol.htm. (This utility requires the NIC's MAC address; see "Finding a Connection's MAC Address," earlier in this tutorial.) You can also try Googling "wake-on-LAN utility."

TIP When you use the wake-on-LAN feature, you probably don't want the remote computer to wake to the Windows 7 Welcome screen. Instead, it's almost always better to have the computer wake directly to the desktop. To disable the password requirement on wakeup, select Start, type wake, and then click the Require a Password When the Computer Wakes link to open the System Settings window. Click Change Settings That Are Currently Unavailable to enable the options. Activate the Don't Require a Password option, and then click Save Changes.

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In this tutorial:

  1. Setting a Small Network
  2. Setting Up a Peer-to-Peer Network
  3. Changing the Computer and Workgroup Name
  4. Connecting to a Wireless Network
  5. Working with Windows 7's Basic Network Tools and Tasks
  6. Accessing the Network and Sharing Center
  7. Setting Up a Homegroup
  8. Activating Homegroup Connections
  9. Creating a Homegroup
  10. Joining a Homegroup
  11. Accessing the Homegroup
  12. Changing Homegroup Settings
  13. Turning Off Homegroup Connections
  14. Viewing Network Computers and Devices
  15. Displaying a Network Map
  16. Viewing Network Status Details
  17. Customizing Your Network
  18. Managing Network Connections
  19. Opening the Network Connections Window
  20. Renaming a Network Connection
  21. Enabling Automatic IP Addressing
  22. Confirming That Windows 7 Is Configured for Dynamic IP Addressing
  23. Displaying the Computer's Current IP Address
  24. Setting Up a Static IP Address
  25. Displaying the Current DNS Addresses
  26. Specifying the Static IP Address
  27. Using a Network Connection to Wake Up a Sleeping Computer
  28. Disabling a Network Connection
  29. Managing Wireless Network Connections
  30. Opening the Manage Wireless Networks Window
  31. Creating an Ad Hoc Wireless Network
  32. Working with Wireless Connection Properties
  33. Modifying Connection Properties
  34. Modifying Security Properties
  35. Renaming Wireless Connections
  36. Reordering Wireless Connections
  37. Creating User-Specific Wireless Connections
  38. Removing Wireless Connections