default file rule

[Robin M.]

On Tue, 20 Jan 2004, Julian Field wrote:
> At 16:23 20/01/2004, you wrote:
> >in the file filename.rules.conf it specifies to allow or deny files. What
> >happens to files which are not listed in this file? i.e. .doc extension is
> >not in this list. Is there a default action ?
>
> The default is to allow it.

Why are there rules which specify to allow certain files? or rather is it
possible to change the default rule?