Web Filter
From UntangleWiki
About Web Filter
Web Filter filters web traffic to your protected network for inappropriate content. Unlike other Software Products, the criteria that Web Filter uses is subjective. Web Filter blocks content by the following:
- Categories (for example, Gambling)
- URLs
- MIME Types
- File Extensions
Blocking Web Filter for Specific Websites
The default Block List blocks most undesirable content based on subject matter or categories. You also have the option to add specific websites, using the following procedure.
Note: If you want to improve the overall product by contributing domain names or URLs that you feel should be blocked by default, check out the Web Filter Submission Tool.
To block content from a specific website:
- From Web Filter, click the Block Lists tab, and click the URLs tab.
Figure, Blocking by Subject Matter - In the table, click the add (plus) button to the left of the table.
- In the new entry, add the URL that you want to block.
Tip: If you want to temporarily unblock this website later, deselect the block check box.
Unblocking Web Filter for Specific Websites
If your organization deems a specific website to be useful and that website is being blocked because of its content or category, or you no longer want to block a website that you specifically blocked, you can unblock it with the following steps:
To unblock web filter for a specific URL blocked by a category:
- From Web Filter, click the Pass Lists tab, and click the URLs tab.
- Do one of the following:
- If the URL that you want to unblock appears in the table, select the pass check box for that URL.
- If you need to add a new URL, click the add (plus) button to the left of the table, and in the new entry, add the URL that you want to unblock.
- Click the Save Settings button.
To unblock web content for a specific URL blocked by a user-defined URL:
- From Web Filter, click the Block Lists tab, and click the URLs tab.
- Do one of the following:
- In the table, select an existing URL that is being blocked, and deselect the block check box.
- In the table, select the row that corresponds to the URL that to want to unblock, and click the subtract (minus) button to the left of the table.
- Click the Save Settings button.
Blocking/Unblocking Delays on Category/URL-based Filters
Whenever the status of a block changes, there are associated delays before the change is visible.
Blocks Based on Category
Catgeory blocking is driven by a database that is part of the Untangle system. The database is downloaded and initialized when the system is created, and is updated whenever the Untangle administrator requests that a catgeory change status from blocked to unblocked (or vice versa). Additionally, this occurs every six hours. This assures that your category database is up to date at all times. This change causes the database contents to be deleted and reloaded from scratch, resulting in a delay of approximately five miniutes before requested changes take effect. In future releases, only database changes will be downloaded and installed, so changes will be instantaneous.
Blocks Based on a Specific URL
When a specific URL is added or removed from either the Block List or Pass List, there are also delays. These are related to the "lifespan" of a web page (as defined by the web server which transmits the page), and the cache settings of the user's browser. You have no control over the page lifespan, but your browser may allow you to shorten and/or eliminate the use of browser caching. If your browser cannot use the cache, it cannot load a copy of the requested page from its cache, so blocks would immediately occur. Also, testing a block on a web page that is currently loaded causes confusion (unless caching is turned off) because the page will still load.
Unblocking Web Filter by Subject Matter
The default Block List blocks a lot of undesirable content. However, if your organization deems such content to be useful, you can unblock content for a specific subject matter.
Tip: To prevent help desk costs in the event that users call your company's help desk to request access to a blocked website, identify the users that require special privileges—before you block websites. You can do so by logging all website access in order to monitor who needs special privileges. Once you identify these users, create a virtual rack for these users.
When a user within the protected network browses a site selected in the Category tab, the user receives an error message, which informs the user that Web Filter blocked the user's request. The error message also states the category (Web Mail, Gambling, etc) of the site in question.
To unblock web filter by category:
- From Web Filter, click the Block Lists tab, and click the Categories tab.
- In the table, select the row that corresponds to the category that you want to block or unblock.
- In the drop-down list box, select one of the following:
- pass
- pass and log
- Click the Save Settings button.
Unblocking Web Filter for Specific Users
If you only have a few users that need to bypass web filter controls, consider using pass lists, not a separate virtual rack.
Before You Begin: Assign the user a static IP address. If the Untangle Server is your router, go to Assigning Network Computers Static IP Addresses.
To unblock web content for specific users:
- From Web Filter, click the Pass Lists tab, and click the Clients tab.
- In the table, select the plus (add) button. A new row appears.
- In the client IP address text box, specify the computer IP address of user that you want to be exempt from the web filter.
- Click the Save Settings button.
Blocking Web Filter by MIME Type
To block content by MIME type:
- From Web Filter, click the Block Lists tab, and click the MIME Types tab.
- In the table, do one of the following:
- If the MIME type that you want to block appears in the table, select the block check box for that MIME type.
- If you need to add a new MIME type, click the add (plus) button to the left of the table, and in the new entry, add the MIME type that you want to block.
Blocking Web Filter by File Extension
To block content by file extension:
- From Web Filter, click the Block Lists tab, and click the File Extensions tab.
- In the table, click the add (plus) button to the left of the table.
- In the new entry, add the extension that you want to block.
About Web Filter Event Log
Use the following terms and definitions to understand the Web Filter Event Log:
timestamp The time the event took place. action The action which the Untangle Server took on the web request. client IP address of the client who made the request. request A description of the request made (e.g. http://someurl/somepath.html). reason for action The reason the action was taken. server The server IP Address. The server is the computer that receives the request.
