I have a linux server running RHEL 5.1 x86 (the distribution doesn't matter since the same happens on SuSE.). Using wake-on-lan, I can wake up it if it was shutted down by "shutdown -h now" or "echo disk > /sys/power/state". Since waking up from such a state implys long start-up time, I'd rather it stays "standby" or "sleep in memory" by command "echo standby|memory > /sys/power/state". Although it can be waken by pressing power button, it does not respond to a wake-on-lan packet.

To make sure WOL works, I checked BIOS and it said: "Wake On Lan:enabled"; I issued command: 'ethtool eth0' and it said: Supports Wake-on: umbg
Wake-on: d
;

I'm confused. Does linux in "standby" or "memory" power mode can be waken up by wake-on-lan mechanism? If the answer is no, is there a way I can remotely wake it up?

Wake-on: d means it is disabled, so enable it with
ethtool -s eth0 wol g

If you want the setting to stick after a reboot you could add the same line to your start up scripts.
I can't find evidence of linux supporting WoL from suspend to ram

You might also look at /etc/sysconfig/apm-scripts/ if that directory exists. You might be able to influence the suspend/hibernate procedure from there. These control Automatic Power Management on RH.
http://www.linuxtopia.org/online_boo...sconf-dir.html

Thank you for your reply, smoker. I'm sorry that "Wake-on: d", which should be "Wake-on: g", is a clerical mistake I made. I typed this line instead of copy-and-paste for I posted on windows.

"/etc/sysconfig/apm-scripts" directory does not exists on my linux.I'm still not sure if linux can be WoL from standby mode. Maybe I need to install suspend-scripts.