No matter your reason, there are times when you need to be able to block access to certain Web sites. The biggest problem with this process is keeping users from viewing the thousands upon thousands of black-listed sites you do not want them to see. A better solution is to employ a white list of sites that only allows users to see the sites that you have configured to allow them to see.
There are plenty of applications out there that will allow you to control browsing via white lists. But none of them is as simple and as effective as ProCon Latte.
Of course, you might be asking yourself, "What good is a Firefox add-in to block users when the users can simply disable it?" Fortunately, the developers of ProCon Latte have thought of this as well. You can password protect this white-list filter so that only authenticated users can change the settings or disable the plug-in.
And ProCon Latte is cross-platform ready with install candidates for Linux, Windows, and Mac, and it works with Firefox 2.x - 3.x.
Getting and installing
As you would expect, installing ProCon Latte is as simple as installing any other Firefox extension. You visit the ProCon Latte extension page, click on the Add to Firefox button, agree to the license agreement, and restart Firefox when prompted.
What to do now?The first thing you need to do is open up ProCon Latte. To open up the Latte window, go to the Tools menu and select ProCon from the list. This will open the main window where you can take care of your configuration (Figure A).
Upon installation, the only aspect of ProCon Latte that is enabled is the Explicate Material Filter.
General settingsIn the General Settings window (Figure B), there are plenty of options. You can immediately see, in the left pane, the status of each of the filters.
If you see a green check by the status of a filter, it is enabled.
In the General Settings window, there are three particular settings you want to take care of right away:
- Set Password
- Prevent from Being Disabled or Uninstalled, and
- Lock about:config
In order to set a password, click the Set Password button and enter the password twice. Once you have done this, the user will have to enter the password in order to open the ProCon Latte window.
But don't think you are finished with locking this down simply because a password has been set. The smart user could enter "about:config" in the URL bar, search for the ProCon entry, and disable it from there. Fortunately, you can disable the ProCon entry from about:config.
You will also want to check the Prevent from Being Disabled or Uninstalled entry. This will keep your users from opening the Addons window and disabling ProCon from the list of installed Addons.
Set up your white listTo set up your white list, all you have to do is go to the White List tab and configure the sites you want to allow. You will see three sites already included in the list (Figure C). First you must actually enable this feature by clicking the Enable Whitelist check box. There are two ways to add a site to your white list. You can either hit the Add Current Site button or type the URL (one URL per line) in the text area.
Once enabled, only the sites in this list will be available to the user.
After you are satisfied with your white list, click the OK button to finish. Now Firefox can visit only those particular sites.
There is another way to add sites to your white list that is even easier. From the General Settings window, if you select Enable Right-click Adding to Whitelist, you can then right-click anywhere on a Web site and you will see a new ProCon menu entry. From this new menu entry, you can select Add Current Page to Whitelist to immediately add the page.
If you want to block all traffic except white-listed sites, you will need to go to the Main Filter tab of the options window and select the entry Secure.
Various filters and settings
ProCon Latte contains a few other filters. You can enable a profanity filter that will allow you to enter single words (one per line) to filter. You also have to make sure you enable this filter before it will work.
There is also an explicit material filter that allows you to block Web sites based on key words. In this window you simply click on key words (such as Adults Only) and add them to the list. Once these sites are added, ProCon Latte will filter out any content based on those key words.
You can also enable specific messages that will be displayed when a user has attempted to visit a forbidden site. This is done in the Main Filter tab of the Settings window. If you don't want to just display a message, you can choose to redirect to another page all together. This is done in the same window.
If you are looking for a tool to filter Web traffic for users but you don't want to add third-party software, the Firefox add-on, ProCon Latte, is a simple solution that allows you to easily set up filters based on white lists, explicit material, and profanity. Of course, if you're looking to deploy this on a large scale, this would require imaging or creating a custom installation script. If you're looking for a smaller deployment, installing ProCon Latte is a simple solution to a challenging problem.
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Jack Wallen is an award-winning writer for TechRepublic and Linux.com. He’s an avid promoter of open source and the voice of The Android Expert. For more news about Jack Wallen, visit his website getjackd.net.