Restricting the downloading of .exe,.zip files

[Marty Williams]

Having recently come across a situation in one of our libraries (a joint use school / community) where a clever lad downloaded and installed a pice of software that logs all logins we are obviously concerned about the security implications. As a possible solution I would like to know if anyone has found a means of restricting the files that can be downloaded from the web? If we could ensure that executable or zipped files cannot be downloaded, this would go some way towards prevention.

Any other lines of attack are also welcomed.

Thanks

Marty Williams
www.terra.net.au/~marwil/cool/home.htm