Wakupator

Wakupator is a lightweight C-based service that monitors incoming network traffic on spoofed local IP addresses and sends IEEE 802.3 Wake-on-LAN magic packets to registered machines. It lets machines register IP/port rules before shutdown so they can remain powered off until relevant traffic arrives.

Key Features

• Spoofs IPv4 and IPv6 addresses on the host to detect incoming TCP traffic for specific IP:port pairs.
• Simple TCP registration protocol using a JSON payload (mac + monitor entries) to declare which IPs/ports to monitor.
• Sends Wake-on-LAN magic packets with configurable number of attempts and intervals; reports boot time and retires clients when awake.
• Handles IPv6 Duplicate Address Detection workarounds via sysctl adjustments and uses iproute2 to add/remove spoofed addresses.
• Minimal C implementation with a small dependency footprint (uses cJSON for JSON parsing) and examples for systemd service integration.

Use Cases

• Save energy for home servers or lab machines by waking them only when needed (game servers, SSH, etc.).
• Host services on low-cost always-on hardware (e.g., Raspberry Pi) that wakes heavier machines on demand.
• Small office or homelab setups where availability can be traded for lower power usage.

Limitations and Considerations

• Requires CAP_NET_RAW (or root) and the ip and sysctl tools from iproute2 and the OS; must be run with sufficient privileges.
• Not safe to expose to the Internet; intended for local LAN use only and can interact poorly with services bound to 0.0.0.0 or :: if host firewall rules are not tightened.
• Incompatible with networks or routers that enforce static IP/MAC bindings; initial client connection attempts may timeout depending on boot time.

Wakupator is a focused, low-level tool for reducing idle power use by waking specific machines on incoming traffic. It is best suited for technically proficient users who can manage OS networking privileges and local firewall rules.