Bandwidth leeching

Terry Thibodeau — Thu, 20 Dec 2007 16:04:00 GMT

When I decided to start blogging, I never thought I'd have to worry about things like bandwidth leeching. But while checking out my traffic stats the other day, I came across this referring link that had a very familiar image on it:

*original* content in screenshot is from this site

I choose to license all content on my blog under creative commons, which means you can feel free to re-publish anything you like from my site, with credit to the original author.

I'm not upset about the fact that my beautifully prepared image is being hosted on someone else's site. I'm upset that there was no credit given for my mad Photoshop skillz and that this person didn't even bother to host the image file on his own server! Why is this bad? Well, instead of using his own bandwidth, he is choosing to let people download this image from my site directly, allowing me to incur the bandwith cost.

This may be a case of "I didn't realize this was bad". If so, that's fine. I will gladly allow my image to be reused (with credit) as long as the image is hosted from your own server.

LeechGuard in action

How can you prevent bandwidth leeching?

There are quite a few tools out there that you can purchase to prevent "hot-linking". However, since I love FREE tools, I will point you to the awesome, FREE utility by Mike Volodarsky, Program Manager on Microsoft’s IIS team: LeechGuard.

LeechGuard is a custom HttpModule that handles requests for the resource types that you specify in the web.config (gif, jpg, etc.). If a request for a file is made (Nostalgia.png, in this case) and the extension matches the configured types, LeechGuard can redirect to a different image or return an HTTP error code (example: 403 - Access denied) if the referring URL was not your own site.

There is a small performance hit by funnelling every IIS request through the ASP.NET ISAPI filter (the preferred method of configuration), but it's a small price to pay to know that your bandwidth is YOUR bandwidth. :)

Terry Thibodeau's Blog : .NET, tools

Bandwidth leeching