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What is Content Filtering & How Does it Block URLs?

The internet has permeated nearly every aspect of our lives. It’s where we work, learn, stream music and videos, find solutions to health issues, and shop online stores. The internet is our everything. While it has plenty of benefits, such as convenience and efficiency, it comes with risks.

It’s well known that there is a dark side to the internet—the dark web. This contains vile images, illegal weapons, stolen IDs, and so much more. The problem is, you don’t have to go that deep to find inappropriate content. In fact, web searches for even the most innocuous things can yield unsavory results. This is where content filtering comes in.

What is filtering for the web? We’ll cover everything you need to know about content filtering below.

What is Content Filtering?

Content filtering is a program that blocks all sites or pages you deem inappropriate. These may be sites that are dangerous, distracting, or unsavory. With most content filters, you’re able to block specific sites or use keywords to block associated content. Say, for instance, you want to block sexual content. You would use keyword filtering with related words, such as sex or porn, to block all search results related to those terms.

Content filtering tool: GoGuardian Admin

The type of content you filter depends on the environment it’s used in. Content filters in the workplace are often included in the firewall infrastructure as software or hardware. If this is the case, the content filter's purpose is to protect against cyber threats such as phishing or malware. Or, the company may be using the filters to block employees from distractions such as social media and streaming services.

In schools, content filters are commonly used to protect students and keep them away from distracting sites. This may include blocking social media, forums, games, or inappropriate sexual content. It may also protect students against cyberbullying, hackers, and scammers. Cybercriminals often target schools due to their large databases of personal information and opportunity for identity theft. However, much worse can happen if that information is in the wrong hands.

What is Content-Based Filtering?

Content-based filtering, or cognitive filtering, is commonly used by Google to filter searches and recommend results based on the term as well as the user. If your search term appears highlighted in the description, that’s content-based filtering. If you’ve searched the same term or similar terms several times, the search engine will remember this and  will continue to provide related options. Each time you complete a search, it will intuitively get better at knowing what you’re looking for. 

This is not the same as a content filter. A content filter will block specific material chosen by the administrator to conceal undesired search results. Content-based filtering is a tool used by Google’s algorithm to improve your search results.

How Does Content Filtering Work?

Web content filtering uses software or hardware to block websites or content. It essentially creates rules for the device on which content it can deliver to the user. Most content filters use keywords to block pages, but they can also block specific sites. 

Filters may also work by identifying content patterns such as text strings or specific objects within an image. If these match with the content specified for filtering, the software will block it from the user. 

DNS filtering, or DNS blocking, is another type of filter commonly used by corporations to block specific IP addresses, social media access, streaming services, or eCommerce sites. These filters are set into the router to block all connected devices at once.

How Do I Remove Content Filtering?

Although content filters are useful for protecting children, safeguarding information, and keeping employees productive, they can  also be a hindrance if they block items needed for work assignments. For example, say you want to do a school project on breast cancer. You go to Breastcancer.org and see a message that reads “This domain is blocked due to content filtering”. Most likely, the keyword “breast” is on the blacklist and blocks the site as a result.

Many web filters are set up in the network router. Because of this, filtering occurs on all connected devices, even your cell phone. The easiest way to disable the filter and access the sites you need is to go into the router configuration. Follow these steps to disable a router-configured content filter:

  1. Log into network configuration utility and click on the main settings.

  2. Select “blocked sites” or related label.

  3. Click on the filter you want to remove and select “delete” or “disable”. 

  4. Click “Apply”.

  5. Log out of the configuration.

If the content filter is applied through Google Safe Search, there are alternate steps to disabling it. Bear in mind, only administrators of the filter can access the settings, although access is possible if the settings are not locked. The settings page is where you'll need to go to lock and change blocked pages. Once you lock the setting, it will then only be accessible by password. Safe Search settings are a little less robust than other filters. They generally block huge chunks of content at once, without specification. If you’ve tried the filter, but later realized it was blocking content needed by students or employees, you can easily disable it.

  1. Go to the Google search preferences page and find the address under “resources”. 

  2. See “Safe Search filters”. There is a slider to turn the filter off that reads “No filtering”. 

  3. Click “save” at the bottom of the page.

Why Do Schools Block Websites?

Schools have one of the most important roles in the lives of students. They must educate and protect them, which is growing increasingly difficult in today’s digital world.Schools must take action against:

  • Cyberbullying/ bullying

  • Self-harm

  • Suicide prevention

  • Shootings

  • Radicalization

  • Identity theft from hackers

  • Exposure to obscene content online

The difficulty is that schools are often underfunded and spread thin. Teachers are often untrained in many of these concerns.  and lack resources to protect against all threats. Plus, acting against them is the constantly changing technology, the ever-evolving social media, and the persistence of hackers, scammers, and predators who have more time and resources.  

To make it worse, kids are far more dependent on their phones than ever. According to Project Tomorrow, 91% of high school students have smartphones. For middle schoolers that number is 79%, and 50% for elementary students. During class, approximately 68% of students will access those devices. 

Due to these factors, Congress passed the Children’s Internet Protection Act (CIPA). The act provides E-rate program discounts to internet safety policies. To qualify, schools must include content filtering, monitoring, and education in digital citizenship.

The discount may be a great reason to implement content filtering, but it isn’t the only reason. Schools have an obligation to protect their students’ mental and physical well-being, as well as threats they can’t see. As mentioned, hackers target schools because of the personal data stored in databases. Web filtering draws some criticism for censorship, but, the benefits of content filtering far outweigh the negatives.

Can Filtering Software or Hardware Really Block All Unwanted Content?

No, it’s impossible to block every bit of unwanted content because there are 4.5 billion sites on the surface web and grouping all of that information into categories isn’t exactly easy. You could unintentionally block important resources and impede the ability to work.

Filtering may walk the line of censorship, especially if it blocks innocuous sites charged by politics, such as Planned Parenthood. These biases may be self-conscious, or you may not be aware that particular content is blocked.

A comprehensive filter that updates regularly and allows changes is ideal. As your students or employees get used to the search parameters, you’ll gain a better understanding of what content is needed and make changes as necessary. 

Web content filtering isn’t perfect, but the threats online are rising and a filter may be your best defense. 


GoGuardian content filtering and monitoring is one of the most comprehensive filtering tools available. It’s designed specifically for schools and their needs. Learn more about content filtering at GoGuardian


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