Synopsis: This article gives our guidelines on filter configuration.

A filter is something that can be used within a policy to determine whether a site should be blocked or not.

As of this writing, the CensorNet supports the following filters.

Custom URL Filter

This is a single module that combines the old URL Filter and URL Override Filter. This allows you to define categories of URLs that may then be set as blocked in one policy, but allowed in another. Since the Custom URL Filter always takes precedence when a policy is parsed, this module allows you fine grain control over how any particular URL is handled.

Content Classifier

The only configuration you have to do with this is to define when your CensorNet will start to download the classification database to your machine.

When you first install a CensorNet it will operate this module in Online Lookup mode. Checking each URL you visit against one of our CSRV servers. This naturally slows down the overall functioning of the system.

Once you have a full license (not a trial license), then you should also be given a login and password for the CSRV. Simply key these details, plus a URL and a time and the CensorNet will download the database locally, greatly speeding up the module.

We recommend that you set it to run overnight. The first time it runs, in particular, it will run for several hours as it has a lot of data to download and process.

File Type Filter

This filter contains a list of the most common file type extensions. You can add additional extensions if you find an extension that is not in our database. Then, in a policy, you can configure it to block certain types of file based on that extension.

MIME Type Filter

Every time you visit a page, the web server hosting the page sends your browser back an indication of what sort of information it is sending by giving it a MIME type. Consequently, you can configure the CensorNet to block certain types of file based on MIME type.

Active Image Control

The Active Image Control (AIC) module checks images, helping to cut down those which might contain too much flesh tone. Within a policy, you can configure the AIC to be ""High"", ""Low"" or ""Off"". In addition, there is a sensitivity setting which is applied globally.

Upload Module

Whilst the other modules control what you may be able to see, or not see when downloading data to a workstation, the Upload Module is concerned with controlling what files may be sent via WebMail? systems. With this module, for example, it is possible to block sensitive company documents being uploaded via sites such as Google Mail, Yahoo, or MSN.