[squid-users] urlpath_regex negative assertions

[Vieri]

Hi,

I'd like to block access to URLs ending in *.dll except for those ending in mriweb.dll.

acl denied_filetypes urlpath_regex -i denied.filetypes

where denied.filetypes contains a list of expressions of which:

(\?!mriweb\.dll$).*\.dll$

This doesn't seem to work if I try to deny access.
eg. an http client can access http://whatever/mriweb_test.dll when it shouldn't.

Where's my mistake?

Thanks,

Vieri