Honestly, WOL works great if
you have the correct gear. If you start 'hacking' or using workarounds you NEED tcp/ip knowledge and know what you are doing. All the tricks (one which I just learned today) and knowledge appears to be present here. The only thing I would like to remark is that you have to keep in mind WOL is a layer 2 technology. It has nothing
to do with IP-addressess.
Wake on wireless lan is also possible, giving you have the correct gear.
For wake-on-wan (over the internet), I first tried my lan's (which only has 1 subnet) broadcast address. As expected, the router refused to flood this to the subnet. A good thing that is, because it imposes a security risk. Those willing to accept that risk should, in my opnion, be provided with the means to alter this behaviour. But nonetheless, a router IS supposed to seperate broadcast domains so it is working as intended. So the thing the router is NOT doing here, is allowing IP-directed broadcasts
. Higher-end gear does allow this but I'm betting those who use it, do not have their WAN directly lead to the big bad internet.
I was lucky enough my Speedtouch modem/router allowed adding static ARP entries. This won't mess up your lan if you make sure to assign a fixed IP to the computer whose MAC-address had been added to the router's ARP table. If the computer is allowed to DHCP freely, and another IP-address corresponds to the same MAC-address in the ARP-table, mayhem will occur
. Instead of directing the magic packet to the broadcast address, you can now direct it to the static IP-address of the computer you wish to wake up (more on this later!
). After all, the router does not have to ask 'who has ip x.x.x.x' in order to obtain the correct MAC-address: it already has this mapping in its ARP table. As already mentioned in this thread, if the mapping is dynamic, it will get cleared after some time. In some routers this time can be adjusted though, but usually not to prolong it indefintely. This clearly shows the dynamic nature of the mapping. Once it is cleared, WOL over the internet will not work any longer.
Instead of directing the magic packet to the broadcast address, you can now direct it to the static IP-address of the computer you wish to wake up (more on this later!)
I have earlier said, IP-addresses have nothing to do with WOL, which might make my above quote look seemingly untrue. I will now clarify this. IF I were to choose a random IP in my subnet (it doesn't even have to be assigned to a computer) and direct/forward the magic packet to that random IP (which would of course have to contain a valid MAC-address), the computer with the static IP-would also wake up given I have paired a valid MAC-address with this 'ghost'IP:
Say the static IP is 192.168.1.10. And the random IP is 192.168.1.200. If I make a static entry with the random IP and the MAC of the computer having the static IP, the WOL will also work (and that may very well be all what would still work haha). This should illustrate the IP-address is not used for WOL itself, it is here, however, used find out the MAC-address.
The underlying problem is that many people are now want a bite of enterprise applications. And manufacturers have not caught up to these wishes yet. The Speedtouch can do it because its firmware is based on way more expensive devices and this is sort of a telnet hack (as there is no way to add static MAC parings via the gui). If you want easy sailing, it will cost some money. Or you could look for alternative firmware like DDWRT, which provides a page with a 'WOL-button' and, if I'm not mistaken, can be configured (through SSH) to allow IP directed broadcasts. But in that case you need to be at easy with flashing your router and perhaps, if done wrongly, bricking it.
I hope my ramblings have been somewhat informative to future readers
. Do slap me on the head if I missed anything. I did do my best to provide correct information!