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Content Filtering – How do they work?

A content filter is the screening of an incoming web page to determine whether some or all of the page should be displayed or not be displayed to the user. The filter will check the origin or content of a web page against a set of rules and categories within the software and either allow or block the page for the end user.  The district is required by Board of Education Policy EHB Technology Usage and by federal law to have a content filter in place if we receive federal funds for Internet service.  As a public school district, we do utilize eRate funds which are federal funds to help subsidize the bandwidth we need for Internet use.

The Q and A below was built to help staff and students understand how the district’s content filter functions and the procedures that are in place to ensure safety, security and functionality for the staff and the network.



How do content filters work? There are multiple features that are leveraged to determine content filtering. Content filters primarily use technology that blocks sites by categories.  For example we are required to block any website that has a categories of pornography, gambling, etc.
What is required to be blocked by law?

A public school district is required to filter at a minimum level per CIPA (Children’s Internet Protection Act). Here is a link to more information from the Federal Communications Commission.

At minimum the district must block or filter Internet access to images and photos that are: (a) obscene, (b) child pornography, or (c) harmful to minors (for computers that are accessed by minors).

Web sites that are likely to include objectionable advertising, pornographic content, hacking sites, viruses and other objectionable content are also filtered out for staff and students.

What categories does the district block by age level?

Elementary: Anonymous Proxies, Chat/Messaging, Gambling, Hate, No Safe Search Search Engines, Other Adult Content, Pornography, Social Media, Social Networking, Streaming Media, Web Mail

Middle School: Anonymous Proxies, Chat/Messaging, Gambling, Hate, No Safe Search Search Engines, Other Adult Content, Pornography, Streaming Media, Web Mail

High School: Anonymous Proxies, Chat/Messaging, Gambling, Hate, No Safe Search Search Engines, Other Adult Content, Pornography, Social Media, Web Mail

Why can’t the district just open all websites that are not against the law or illegal? The district’s main goal is the education of our students.  The Internet is one of those resources we use for instructional purposes.  On our network, over 22,000 users share the Internet bandwidth.  Therefore we have to be aware of sites that could potentially be a bandwidth “hog,” taking away from the overall flow of our network to end users.  An example of this would be Netflix or Spotify which are filtered in the category of Streaming Media.  Although these sites are used personally by staff and students, they are not part of the instructional curriculum.
What should I do if a website needed for a lesson is blocked by the content filter? The technology department has a process in place which allows teachers to submit a request to open sites they feel are critical to their instruction.  As long as the site is not in an illegal category or a category that would allow traffic detrimental to the network, we would allow the site through the filter.
Can a website be blocked if it is currently in the wrong category? Absolutely. There are sites that are blocked simply because the category assigned to the site is incorrect.  There is a process for teachers to submit a ticket for technology to review the categorization and open the site.
What happens if a student finds a way to avoid the content filter? As found in the handbook and in the District’s Board Policy EHB “Technology Usage,” evading or disabling, or attempting to evade or disable a content filter installed by the district is prohibited.  
Does the content filter block everything that the school does not want students to see? No content filter is 100% accurate all the time because they all run off of the “category.”  If a website is miscategoried, then it could potentially get through the filter.  If we find sites that are miscategoried, we report them to our service provider.