Wake on Lan

[idata]

I have a Dell Inspiron 530 Desktop running Windows Vista, with an integrated Intel 82562V-2 10/100 network adaptor, using version 9.13.41.0 network driver, dated 3/26/10. I have my PC's BIOS and network card configured for WOL, using both 'Wake on Magic Packet' and 'Wake on Magic Packet from Power Off State'. The PC will always power up correctly from an S(5) state via the Magic Packet if I send it through my LAN.

However, here's where the problem comes in... if I initiate a WOL request from outside my network (through the Internet - WAN), the PC will only power up if this action is taken within <2 minutes from a normal PC shutdown. Otherwise I have to be on my LAN, or power the PC back up via the power button.

My question... I can easily boot the system from a total power off state (S5) using any number of available programs, as well as my Ipod 4th gen from any outside network (WAN). However it will only do this within <2 minutes of shutting the system down. After that I have to resort to waking the system up through my LAN or the power button. I want to do a WOL over the Internet (WAN), and while away from my local network. What is causing this and how do I resolve it?

I don't believe it is a port forwarding issue (I've forwarded port 9 in my router to my desktop's Private IP), it is not an Ipod APP issue (because it works within that <2 minute window), it is not a Windows Firewall issue (remember it works within <2 minute window).

Is it related to my Dell 530 integrated network card??

Again, I can easily turn my PC on from a total powered off state at any time from within my local LAN. I can also turn my PC on from a total powered off state from OUTSIDE my local LAN (WAN), but only if I perform the task within a <2 minute period from shutdown.

I'm open to all suggestion and ideas. It's driving me a bit crazy!!!