Typically, a computer's Ethernet port stays alive via the +5VSB (Standby Voltage) rail from the power supply. When the UPS enters deep discharge or "sleep" mode (after a low-battery shutdown), it often cuts all outlet power to save the battery.
If you enable "AC Power Loss: Power On," you technically don't need WoL at all! When the APC UPS finishes recharging and re-energizes the outlets, the PC will boot as if you pressed the power button. This is the "Best" fail-safe for APC UPS users. Part 3: The Windows & NIC Driver Settings (The Hidden Kryptonite) Even with a perfect APC UPS and BIOS, Windows updates often kill WoL. apc ups wake on lan best
| Setting | Recommended State | Why it matters for UPS | | :--- | :--- | :--- | | | Enabled | Obviously. | | PCIe Device Power On | Enabled | Allows the NIC to trigger boot. | | Deep Sleep / ErP Ready | Disabled | CRITICAL. ErP (Energy-related Products) mode cuts +5VSB to the NIC to save 0.5W. This kills WoL after a UPS shutdown. | | AC Power Loss / Restore | Power On | THE MOST IMPORTANT SETTING. When the UPS restores power, the PC should turn on without needing a Magic Packet. | | S5 (Soft Off) State | OS Controlled | Ensures the NIC stays partially lit. | Typically, a computer's Ethernet port stays alive via
Can't wake your server if the power glitched? Here is how to configure the "Holy Trinity" of remote access: APC UPS + Wake-on-LAN. When the APC UPS finishes recharging and re-energizes