We are using squid 2.6 and Websense as a url_rewrite_program and would like to return a 404 to clients who ask for a particular file ( http://www.example.com/sametime/stlinks/DebugLevel.class). We have explored chaining using zapchain but do not want to use adzap. http://adzapper.sourceforge.net/scripts/zapchain Can we chain using a combination of the zapchain script and the custom.plexample from this link http://www.powershelladmin.com/wiki/Linux_squid_proxy_url_rewriting_or_redirection by specifying this in the squid.conf? url_rewrite_program /opt/zapchain/zapchain /opt/custom/custom.pl /opt/websense/websense or url_rewrite_program (/opt/zapchain/zapchain /opt/custom/custom.pl /opt/websense/websense) Can anyone recommend another approach?