Save Energy! – Power Up Your Home Linux Box From Behind Your Work Proxy Using Wake On LAN (WOL)

pwrbutton1These days with the price of electricity being so high and with computer power supplies being so big, not to mention the global warming / climate change factor, leaving your home-server running all day while you’re out at work on the off-chance that you might need to access it during the day is a luxury most people can ill-afford.

In an ideal world you would be able to switch on your home server remotely from your work laptop when you’re away from home. Maybe you need to log in via SSH or FTP (if these ports are not blocked by the proxy) or maybe you have it set up as a web server for development use (as I do) and would like to use some of your office downtime to work on something on your dev server. Once you’re done you can then switch it off again with a shell command.

All of this is easy enough to do so long as your home server’s connection to the internet is via an ethernet card that supports Wake On LAN (WOL). You can send a “magic packet“, a string of characters specifically formed to wake your server up either directly from your windows laptop or, if you are behind your company’s proxy server that blocks traffic on port 9, from any internet webserver.

Pre-requisites

This article will describe the steps that you need to take in order to configure this energy-saving functionality. I am assuming the following:

  1. your home server is running Ubuntu/Debian Linux (although it should be possible to use any flavour of Unix/Linux).
  2. the server is connected to the internet with a cable via an ethernet card that supports WOL
  3. your server has a static IP address at least within your home network. (If your ISP changes your IP address periodically like mine does then you will probably need to either pay them extra for a fixed IP address or use a dynamic DNS service)
  4. you have FTP write access to a webserver connected to the internet that supports PHP scripting
  5. you have about an hour of spare time.

Continue reading