Censorship for WWW

David J. Bianco (bianco@MiSTy.larc.nasa.gov)
Fri, 2 Dec 1994 11:09:18 -0500

Simon Reed writes:

> Would it be possible from a programming pov to run a filter along with
> existing browsers which would only permit access to a limited (pre-approved)
> set of adresses? IOW, that way a teacher could permit access to say,
> SpaceLink or the Smithsonian (or whatever) while denying access to other
> sites? Any ideas, anyone?

leaving aside the question of whether or not this is desirable (I have
doubts yet), it's extremely possible. The HTTP proxy method is a
*great* way to implement document filtering. For an example of how
proxies can be used as filters, see :


I originally wrote these to demonstrate the feasibility of
prefiltering HTML documents before they are shown to the client.
Although these filters are meant as humor, the range of application is
quite broad...

David J. Bianco Chair, NASA Webmasters Working Group
Computer Sciences Corporation, http://ice-www.larc.nasa.gov/webmasters/
NASA Langley Research Center Personal Info:
<d.j.bianco@larc.nasa.gov> http://www.larc.nasa.gov/~bianco/bianco.html