"Wake for network access" not working

Is the other computer on the same physical network segment, plugged into the same switch? Wake on LAN doesn't work reliably under other circumstances.

Do you own a very recent model of Apple Airport Extreme base station?

"Wake on network" doesn't just wake for any network traffic. The standard puts the the machine to sleep while allowing the network card to watch for a specially crafted packet - not just any packet will do. If the correct type of packet is received, the network card will wake the machine.

Apple's Airport Extreme Base Stations (only the newer models -- older models wont work) know how to send the correct packet type and work with Bonjour if any Apple service is invoked (e.g. file sharing, screen sharing, printer sharing, etc.) What really happens is the router notices the attempt to reach the machine and sends the correct "wake" packet.

Very recent Macs can wake on either Airport or Ethernet. Slightly older (but still fairly new) Macs don't support wake via Airport wireless but do support wake on physical ethernet cable connections.

Run "System Profiler" (it's in "Applications" -> "Utilities" -> "System Profiler"). In the left-margin select "Airport" (it's in the "Network" section), then check the information displayed on the right. Near the bottom is "Wake on Wireless:" -- next to that it'll indicate if it is supported or not for your particular Mac. It needs to mention that it is "Supported" otherwise it wont work for Airport (but it will work if the machine is connected via a physical ethernet cable.)

Also see: http://support.apple.com/kb/HT3774

Message was edited by: Tim Campbell1

There are two implementations of 'Wake for network access'.

The original implementation uses the standard Wake-on-LAN protocol where a special 'magic packet' is sent directly to the machine's ethernet port. The packet has to be specially crafted to include the machine's MAC address and when the port detects the packet it wakes the system.

In this model you cannot just hope to wake the machine via any-old application. The applications aren't actively running on the machine when it's sleeping, so they can't hear the network or know to wake (in reality, the machine doesn't even have an active IP address when it's sleeping, so you can't send a packet to the IP address and hope to wake the machine, either).

The second implementation can wake the machine via different application layer protocols but it requires a compatible base station to manage your network. In this model when your machine goes to sleep the base station assumes its IP address and listens for network traffic on behalf of the machine. When it detects suitable traffic it wakes the machine and you're set.
The advantage with this approach is that it works for a broad range of applications, and you don't need the magic packet, nor know the machine's MAC address. However, you do need a suitable (read: recent, Apple-branded) base station.

Ah, I missed the "Airport is stopped". In any case, the ability to wake the system is trigger by a carefully crafted packet -- not just any packet will do. This is because systems can receive network traffic constantly. If just any packet could wake a system then many systems would effectively not be able to "sleep" at all.

In any case, you would need a fairly recent version of an Apple Airport Extreme base station (with recent firmware). Another computer wont send the correct wake-on-network packet, but the Airport will send it if it sees traffic attempting to reach one of the Bonjour-registered services.

If you don't have an Apple router that supports this, there is another option -- slightly more cumbersome...

You can get a utility (there are many of them) which allows you to send the wake packet. E.g. here's one I found over at versiontracker:

http://www.versiontracker.com/dyn/moreinfo/macosx/24421

I have not personally tested this myself. Also note that it doesn't specifically say it supports 10.6 (although for purposes of what such a utility would need to do, it probably doesn't really matter.)

With an Airport, you don't need to know if the computer is awake vs. asleep -- just use it and the Airport base station will handle it. Without the Airport to handle this automatically it's up to you to use the utility to manually wake the remote computer before attempting to connect to it with anything else.

Hi guys,

I also tried this and it worked. I have an iMac and MacMini plugged directly (via ethernet) into a Cisco Linksys WRT 610N router. I used the same WakeOnLan app as linked in this thread. The application just sits on your dock while running. It scans through and finds all Mac compatible devices and allows you to wake and sleep all of them remotely.

This is perfect as I use my MacMini as a media-centre, but want it to sleep in between. I basically leave PLEXAPP running all the time so adding to it usually means copying from my iMac to the MacMini remotely. Makes it easy if I can wake remotely and copy, then put back to sleep.