Magic Packet (wake on LAN) doesn't work in Snow Leopard on iMac?

It is indeed part of the snow leopard to have wake on demand enabled. However you need to have an airport supporting this feature. If you previous application did work on leopard it may be just a question of compatibility on snow leopard. Check the developer of the application that you were using if it runs in Snow leopard although it may be redundant to have a 3rd party software to do a feature that a snow leopard can natively do 🙂

the old Wake on Lan works just fine here. I use it. I don't know why it's not working for you. I use this
http://www.readpixel.com/wakeonlan/.

the new feature is only available on newer macs and only if you have an AEBS or Time Capsule as a router.

Message was edited by: V.K.

eric4_4 wrote:
VK - I'll try that app from my wife's MacBook and see if that works. Maybe something changed and there is a different port or UDP packet type that is now required?

not that I'm aware of. I really don't know what the problem is. to be completely specific, I have a powerbook running leopard and a mac pro running snow leopard connected by ethernet via a linksys router. each can wake the other using wakeonlan app.

I have the same problem on my Mac Pro: regular wake-on-lan stopped working since I've upgraded to Snow Leopard, whether or not 'wake on demand' has been enabled.

It's really annoying, because I use it to wake my machine for ssh when I'm working from home: I ssh into another machine on the same subnet, and issue a wake-on-lan packet to my workstation's MAC address.

I think I've found the answer: Snow Leopard is more strict about the 'magic packet' that wakes up the machine; some wake-on-lan utilities (like Debian Linux's 'wakeonlan') now send packets that won't wake up a Mac, while others (like Debian Linux's 'etherwake') work.

Just looking at the source codes of both wake-on-lan utilities, it looks like it's specifically done to disallow IP broadcast packets to be used as wake up packages - you have to send a raw ethernet packet.

Hope that helps.

Why do you think that "Snow Leopard is more strict about the 'magic packet'". Can you confirm that? What's your source for that information?

My Mac mini with Snow Leopard also refuses to wake from sleep. ReadPixel's WakeOnLan can't wake it up, JollysFastVNC can't, my own Java app can't. I'm at loss.

Regards

From the SL review at arstechnica...

" The sleeping Mac dilemma

I don't like to leave my Mac Pro turned on 24 hours a day, especially during the summer in my un-air-conditioned house. But I do want to have access to the files on my Mac when I'm elsewhere—at work, on the road, etc. It is possible to wake a sleeping Mac remotely, but doing so requires being on the same local network.

My solution has been to leave a smaller, more power-efficient laptop on at all times on the same network as my Mac Pro. To wake my Mac Pro remotely, I ssh into the laptop, then send the magic "wake up" packet to my Mac Pro. (For this to work, the "Wake for Ethernet network administrator access" checkbox must be checked in the "Energy Saver" preference pane in System Preferences.)

Snow Leopard provides a way to do this without leaving any of my computers running all day. When a Mac running Snow Leopard is put to sleep, it attempts to hand off ownership of its IP address to its router. (This only works with an AirPort Extreme base station from 2007 or later, or a Time Capsule from 2008 or later with the latest (7.4.2) firmware installed.) The router then listens for any attempt to connect to the IP address. When one occurs, it wakes up the original owner, hands back the IP address, and forwards traffic appropriately."

Thanks for sharing that link.

My problem is solved. I didn't understand that in order to get WOL you need to enabele WOD in Snow Leopard - whether you actually want WOD or not.

http://www.frightanic.com/2009/10/19/wake-on-lan-wol-not-working-in-snow-leopard /