Online Tool Store
Wake-on-LAN Packet Builder
Construct a Wake-on-LAN magic packet from a MAC address, with the broadcast address and port settings a router actually needs.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Network
Wake-on-LAN Packet Builder
Frontend preview — no upload or external service.
Magic packet
102-byte magic packet: six 0xFF bytes followed by the MAC repeated 16 times, addressed to 192.168.1.255 on UDP port 9.
How the Wake-on-LAN Packet Builder works
- Enter the target machine's MAC address, in any common separator format.
- Set the subnet broadcast address, not the machine's own IP — the machine is asleep and has no active IP.
- Send on UDP port 9 from a device on the same subnet, and enable Wake-on-LAN in the target's BIOS and network adapter settings first.
The method
A magic packet is a fixed structure the network card recognises while the rest of the machine is powered down.
6 bytes of 0xFF, then the 6-byte MAC repeated 16 times = 102 bytes payload
There is no authentication in the format at all, which is why Wake-on-LAN is a local network feature and forwarding it from the internet is a poor idea.
FAQ
Why does it need a broadcast address?
Because the sleeping machine has no active IP address for the network to route to. The packet goes to the subnet broadcast, every device sees it, and only the card matching the MAC responds.
Why doesn't Wake-on-LAN work over the internet?
Broadcast traffic does not cross routers. Waking a machine remotely needs either a VPN into the network or a device already awake on that subnet to relay the packet.
What has to be enabled on the target?
Wake-on-LAN in the BIOS or UEFI, and the wake option on the network adapter in the operating system. Many machines also disable it in deep sleep states or after a fast-startup shutdown.
How we compare
| Feature | Online Tool Store | A terminal utility | A hosted diagnostics service |
|---|---|---|---|
| Correct packet structure | ✓ | Manual | Yes |
| Broadcast guidance | ✓ | ✗ | Sometimes |
| No install | ✓ | ✗ | ✓ |
| Sends the packet for you | ✗ | ✓ | ✓ |
Wake-on-LAN Packet Builder constructs the payload and is clear that there is no authentication in it, which is why it belongs on a local network only.