WOL is a feature built into most modern PCs and Macs that allows a powered down or sleeping computer to turn on when it receives a special network signal. If you have ever used an Xbox 360 to access Windows Media Center with your PC turned off, you may have noticed your PC powering up automatically. That is WOL in action.

How Wake on LAN Works

Wake on LAN uses what is known as a “magic packet.” This packet is sent over UDP port 9 to a specific device on your network using its MAC address. When a computer with WOL enabled receives this packet, it powers on.

A few key points:

• The device must be connected through a wired network connection.
• The computer can wake from sleep or a powered down state.
• Most modern PCs and Macs support WOL by default.

On a Mac, the WOL setting is found in System Preferences under Energy Saver. On Windows PCs, WOL must be enabled in both the BIOS and the operating system. A quick online search will provide step by step instructions for your specific model.

Tools to Trigger Wake on LAN

There are many free applications that can send magic packets on your network. One of my favorites is iWake for the iPhone, which allows you to send the packet using either your local WiFi or through mobile data.

To send a magic packet, you will need:

• Your computer’s MAC address
• A WOL capable app
• Proper router configuration (explained below)

Why Wake a Computer Remotely?

WOL is extremely useful if:

• You are traveling and need to access files stored at home.
• You want to remote into your PC from work or another location.
• You have a media server at home and want to stream content without leaving it on all day.
• You prefer not to keep your computer running 24/7.

Instead of leaving your machine powered on “just in case,” you can wake it only when you need it and shut it down afterward.

Using Wake on LAN from Outside Your Home Network

If you want to wake your computer from your office, your hotel, or your mobile device, you need to send the magic packet through the Internet. This requires a little additional setup:

1. Find your global IP address
Visit a site like whatsmyipaddress.com. If your ISP does not provide a static IP, use a free Dynamic DNS service. This gives you a hostname (for example, myname.dyndns.com) that always points to your current IP.

2. Configure your router
Your router must know how to forward magic packets to your network. In your router’s admin settings:

• Create a port forward for UDP port 9
• Forward it to your network’s broadcast address, usually 192.168.1.255

This allows your router to receive the packet from the Internet and broadcast it to all devices on your network. The device with the matching MAC address will wake up.

Once this is configured, you can wake your computer remotely and then connect to it through your preferred remote access tool.

Wake on LAN is a powerful feature that makes remote access far more convenient. Whether you use it for accessing files, streaming media, or managing your home systems while traveling, it is a great capability to enable on your PC or Mac.

If you are interested in setting up a home media server that streams content to mobile devices, be sure to check out the related tutorial on this site.

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