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I recently finished a little project that allows me to remote into my home computer from basically anywhere (registered for a free sub-domain and forwarded remote desktop ports from the router to my machine. The next thing I'd like to do is to alter things to allow my machine to wake on lan, probably over a particular router port. This way I won't need to keep my desktop running 24/7 to remote into it.

Here's the question... Is this a stupid idea? What are the risks? Could my computer just be kept running 24/7 anyways from messages (attacks) coming in?

For reference, this is a windows 7 box that I built a few years ago. It supports Wake On Lan. There's nothing special going on with the modem/router too. Thanks

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Note sure whether you are aware, but not all routers will support this type of port forwarding. Since your computer is switched off, it cannot be considered to have an IP address hence the router can't be configured to forward to a particular ip address, but instead has to broadcast the magic packet to all ip addresses. – sgmoore Aug 21 '12 at 16:07
Yes, this is a good point. I'll have to check on this later. I did setup my computer to have a static IP address on the local network. Wouldn't the router still be able to find the mac address in this case since the NIC will still be powered? – Lodra Aug 21 '12 at 17:10
up vote 2 down vote accepted

Well there is certainly potential that your computer could receive WOL packets and remain on 24/7. If power consumption by your computer is your main concern, then yes this could be an issue for you.

Otherwise, all other security principles apply such as virus scan, firewall, only opening ports that you used and making sure those ports are locked down with strong passwords with whatever services you computer is exposing itself to.

If your router allows for remoting on the WAN side with some sort of shell, then you could probably have the router signal the WOL, allowing you to close the port completely to the outside (I'm thinking something like SSH)

Something else to consider is if you could set up a route or packet relay server from your subdomain (not sure what kind of access you have there), so that you can set you router to whitelist a specific machine on the outside for port forwarding designated to perform the WOL.

Hope this helps.

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I'm concerned about both the power usage and the extra, unnecessary use of the hardware. The shell idea definitely has some merit; I'll look into that one. Thanks for your perspective on this – Lodra Aug 21 '12 at 17:01
Actually, I just thought of something else. I already have an open port for the RDP connections. Is there any reason I couldn't simply send the magic packets over that very same port? – Lodra Aug 21 '12 at 17:04
The only concern there is that can you configure the machine to "listen" on that port? Most NIC's I've seen just simply allow you to enable/disable WOL. Heck, I've seem some only use a jumper to enable it. – hydroparadise Aug 21 '12 at 17:08
I suppose I asked the wrong question then. Since WOL is more about hardware configuration than OS configuration, does the receiving end (my desktop) actually need to listen on a particular port to process magic packets? Do ports even come into play at this part of the process? – Lodra Aug 21 '12 at 17:13
On second thought, you can always add a second entry on the router to hit both ports: 3389->IP:3389 and 3389->IP:9 – hydroparadise Aug 21 '12 at 17:13

First off, for anybody to be able to WOL your box, they have to know your MAC.

Second, you don't port forward to your box IP for WOL. Magic Packets are broadcast messages (x.x.x.255) and everybody on the subnet can listen to it, that's how Magic Packets works.

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