or "Last State". When the UPS detects stable utility power and restarts its outlets, the computer automatically boots up without needing a WoL packet. Active Wake on LAN
To ensure your hardware reliably wakes up after a power event, follow these industry-standard practices: Solved: Wake On LAN (WOL) behind a Smart-UPS apc ups wake on lan best
For users looking to automate the restart of their systems after a power outage using an APC UPS, it is important to understand that . or "Last State"
: Set your BIOS "Restore on AC Power Loss" to "Last State" or "Stay Off" . This prevents the system from boot-looping if power is unstable and allows you to manually trigger a WoL packet only when you are certain the environment is stable. : Set your BIOS "Restore on AC Power
| Problem | Why it fails | APC Solution | | :--- | :--- | :--- | | | Battery ran out; UPS cut AC. | Use BIOS "AC Restore" instead of WoL after deep discharge. | | Server wakes up by itself randomly | APC sends "Power Restored" signal; BIOS boots. | Change BIOS to "Stay Off" and rely solely on WoL. | | UPS clicks constantly during brownouts | Voltage fluctuation. | Adjust transfer voltage in NMC or enable "Green Mode" bypass. | | PowerChute shuts down the server immediately | Default timer is 2 minutes. | Extend BATTDELAY to 600+ seconds in ups.conf . |
Your OS can override BIOS settings. You must ensure the Network Interface Card (NIC) stays listening.