The Finnish computer magazine Tietokone has an article on stolen laptops calling home and the police using this to track down thieves.

The article reads like a press release from the proprietary software company mentioned in the article, although perhaps that's just because it only mentions that one company. However, the main point is that by having the stolen laptop report its IP number, police can trace it and recover it.

In the interest of helping Unix users have similar protection, I provide you with the following crontab snippet:

*/15 * * * * wget -q -O /dev/null http://your.home.page/call-home; true

That page does not need to exist, you just need to be able to access the httpd logs for the web server it accesses to be able to find out the IP number. By using a distinctive URL, you make it easier to grep.

Perhaps someone would like to turn that into a Debian package? Add some debconf magic to specify the URL to access, and it should be easily usable. For all the people without a web site of their own, perhaps there would be people interested in operating a server people could use for that. (There's some privacy issues involved, but it's an opt-in thing, obviously, so that lessens them.)

Now, to be fair, the proprietary software package mentioned does more than my cron job. For example, they can take control of the system remotely, and wipe it out and make it inoperable. Personally, I don't want that, since it's a huge security risk, but if that kind of thing interests you, you could enhance the cron job a bit.

For example, it could download the file and verify that it's GnuPG signed with your key, and if so, execute it as a shell script. One of the risks with this is that if anyone ever happens to get a copy of a file you've made like that, say, your web hosting provider, they can put it there whenever they want to, and boom goes your laptop.

I'm sure there are ways around that, but if you want the system, you'll have to solve that yourself.

Edit: Old discussion page.