Some motherboards keep the lan cards powered even in standby mode. This is done by using some lanes in the PCI bus (or the on-board lan). Mine for example does ( the connection light is always on, even when the PC being shut down ); (It also keeps a red led indicating power on on the mobo all the time)
However, if your particular motherboard model doesn't support this feature, then there's nothing you can do.
Is there any way to change settings so that the motherboard keeps the LAN card powered? I have the Asus p5g41t-mlx motherboard that is capable of wool..I have enabled the settings in the bios.by being capable of wol, should it not keep my LAN powered so that it really is possible to wake?