wake on lan stopped working
 

I have a laptop running Ubuntu 10.04 w/ wireless connection to desktop running Windows 7. I had it set up so I could execute a script to send a wakeonlan to the desktop. It worked fine for several weeks, but all of a sudden it stopped working. I've checked my script and it still looks good as far as I can tell. (I'm not that adept at script writing, so I wouldn't necessarily recognize a problem.) I've also checked the Windows machine to make sure the network adapter still is set to allow wake-on-lan.

Does anyone have any ideas how else to debug this problem?

BTW: my wake up script is as follows:
#!/bin/bash
wakeonlan xx:xx:xx:xx:xx:xx

Where the x's replace my actual MAC address.

You connect this laptop through router by wireless or your desktop PC has own wifi card? If second, then this card must have WoW (Wake On Wireless) feature. If by router: are you changed something in configuration recently? Your laptop and desktop are in the same subnet? For best, run some sniffer for ex. tcpdump on desktop and execute your script on laptop, to check what is going on.

wake on lan still not working
 

OK...it took me a while to figure out how to use a sniffer, but I think I've done it. I see no sign in the captured traffic of the magic packet. Specifically, I'm watching my wlan0 interface for any UDP packets, since wakeonlan man pages say the magic packets are broadcast in UDP protocol. That tells me that the wakeonlan command isn't actually broadcasting anything. How can I figure out why and fix it?

You probably have also eth0 interface. Check all interfaces for magic packet, maybe your wakeonlan program send it through other than wlan0. You can also try other tool, for ex. ether-wake.