Having chosen a
policy (see above), the policy in question is parsed as follows.
Stage 1 - checks the
requested URL against the Custom URL module and returns a list of categories
the URL matches - this may be none, one or many. Once the list of categories
has been determined, it checks to see if the policy prefers to block over allow or allow over block. In the former case, if any one category defines
the URL as blocked, then the request will be blocked. In the latter case, the
reverse will be true.
Stage 2 - if no
decision was made in Stage 1, then the requested URL is checked against the
Content Classifier module. Again, the requested URL could fall into more than
one category. Although the checks are carried out as above, if the requested
URL is classified as a Dynamic site and the option Force real-time content analysis is set, then the real-time raters will be called.
Stage 3 - if no
rules have matched so far, CN Pro will wait for a response from the upstream
proxy, then check the content against the Content Classifier again, this time
also analysing content, then the File Type filter, then the MIME Type filter,
and finally, the Active Image Control.
Related Topics