Hi.

I think that YouTube is a fantastic resource for my kids and I would like to allow them to watch some videos, which is a large and rapidly expanding number. I would also like to restrict them from watching videos which is also a large and rapidly expanding number.

Specifically, I would like them to be able to access any video available at "www.khanacademy.org", or "khanexercises.appspot.com". (For those of you who don't know, the Khan Academy provides free videos to tutor people in Maths, Sciences, and other from Grade 1 through University, and khanexercises.appspot.com is a free web application that allows you to test your math skills at various levels).

I know that the every HTTP message tells the server from where the current URL is referred. For example, if you were on khanacademy.org and clicked to YouTube, YouTube would know that khanacademy.org was the referrer just by looking at the HTTP message.

I would like to grant my kids access to any video that linked to from khanacademy.org, khanexercises.appspot.com and a small number of other sites, and restrict access to all other YouTube videos.

Does anybody know of any software or configuration setting that would allow referrer-based web filtering?

The pseudo-code for the code is as follows:

referrer_whitelist = ["khanacademy.org", "khanexercises.appsot.com"]

if http_message.referrer in referrer_whitelist
#allow
else
# disallow or ask for special permission
end

This is a generic problem that could be applied to all kinds of folks that would like to use YouTube as an educational or entertainment resource for a set of sanctioned videos on a white-listed referrer.

Thanks, Jay