I have been using Wake-on-LAN successfully for many years now for a number of my Linux devices. It works well enough.
However, I also have a Mac Mini at home. I have noticed that it goes to sleep and has two distinct properties separate from any Linux machine I have while asleep:
It still responds to ping on the network.
It will wake up automatically upon incoming
sshconnection, no Wake-on-LAN required.
This 2nd property ends up being really nice: it automatically goes to sleep and saves power when not in use and doesn't require any extra thought to power on when I want to ssh into it. It just wakes up automatically. And after I've logged out, 15 minutes later it will go to sleep again.
My assumption is this is because Apple controls the hardware and software stack. So while industry-wide Wake-on-LAN is a network device feature based on a magic packet (that requires no OS interaction), Mac's magic "wake-on-LAN and also still respond to pings" is because they haven't actually put the whole OS to sleep and/or have a separate network stack still running in sleep mode. But that's just a guess.
I'm curious if anyone has ever seen or implemented this sort of "Wake-on-incoming-SSH" on a Linux machine? Or is this special magic that can be found only on Apple devices where they control hardware-through-software and can do this in a way the rest of the industry can't?