What is content filtering and how does it work?

Web content filtering ensures internet environments are safe for schools, universities, and government entities by blocking unwanted online content. Learn how to prevent web-based threats from striking today.

What is content filtering?

While the Internet is an integral part of our lives, we recognize that parts of cyberspace are inappropriate or unsafe for certain users. Some, such as phishing pages or extreme pornography websites, can be quite harmful.

Many parents use SafeSearch at home to protect vulnerable members of their family, such as children. You can think of this tool as a basic example of web content filtering.

Organizations such as schools use more advanced forms of web content filtering to ensure their users only have access to suitable content, and it’s easy to see why. Content filtering technology allows students to learn from the Internet safely. It also helps shield educational institutions from increasingly sophisticated online threats.

For example, K12 schools face threats like phishing, ransomware, and data theft with greater frequency. Web content filtering, in addition to top K12 cybersecurity tools, can protect students and faculty from various dangers while satisfying rules like the Children’s Internet Protection Act (CIPA), FERPA, COPPA and GDPR.

Other organizations, such as modern offices, also benefit from content filtering technology by shutting down threat vectors that spread malware or content that negatively impacts productivity. 

Web content filtering definition

Web content filtering is a kind of process or technology based on software or hardware that restricts access to specific content on the Internet. Organizations such as enterprises, libraries, colleges, and schools use web content filtering to prevent users from accessing potentially inappropriate material for various purposes, including protecting user sensibilities, boosting cybersecurity, enhancing regulatory compliance, and improving productivity. 

How does web filtering work?

The exact way a web content filter works depends on its nature and implementation. Typically, a web content filter analyzes the content of a webpage and leverages a set of pre-defined criteria to determine whether it should be accessible. The pre-defined criteria may help an organization block pornography, scams, malware, and violent media. Some organizations may also use filters to block social media pages or content from their competitors.

Common techniques used by web content filtering include:

  1. URL filters block access to websites based on their URLs.
  2. Keyword filters block content carrying certain words and phrases.
  3. Image and video filters block inappropriate media.
  4. Email and message filters analyze and block access to messages that carry potentially unsafe content.
  5. IP filters restrict access to a range of IP addresses or a specific IP address.
  6. Reputation-based filters prevent users from accessing websites known for phishing attacks, dropping malware, or featuring inappropriate content.
  7. AI-Powered filters use Artificial Intelligence and Machine Learning to analyze web content and block content accordingly.
  8. Content Classification Systems (CCS) block certain categories of websites.

Block dangerous websites. Prevent phishing attacks, malware, and other advanced threats with DNS Filtering.

Foster safe internet environments for schools and universities. DNS content filtering keeps students and faculty safe.


Who uses web content filtering?


Individuals such as parents use web content filtering to improve safety at home. With the right tools, they can block harmful content such as pornography. Web content filters can also block access to pages that promote hate speech or are used by cyber bullies or online predators.


All types of businesses, regardless of industry, use web content filtering to improve workflow by restricting access to distracting content such as social media pages or adult websites. In addition, they use these solutions to optimize network speeds and improve security by filtering web pages where employees may find malware. However, business web filtering is only a small component of a comprehensive cybersecurity framework for a business. In addition to enterprise web content filtering, modern companies also use firewalls, VPNs, anti-malware technology, and the best endpoint protection systems.


Web content filtering helps schools, colleges, universities, and other educational bodies prevent students from consuming unsafe content, getting scammed, or downloading malicious programs. Web content filtering can also shield young students from cyberbullying by blocking social media pages, chat groups, and inappropriate message boards.


Threat actors are using increasingly complex tactics to attack government employees. In addition to sending highly convincing spear-phishing emails, they may try to trick government employees into downloading malicious files in watering hole attacks.

Advanced web filtering systems that leverage Machine Learning algorithms to analyze the content of websites and web-based applications can play a role in protecting government employees from various web-based attacks. Content filtering can also block pages that may be a threat to national security or public safety in other ways, such as propagating disinformation campaigns or selling illegal goods.

Why is web content filtering important?

Protect against malware

Some websites and web-based applications infect users with malware through drive-by downloads, malvertising, phishing, and other kinds of web-based attacks. Web content filtering technology protects users from malware by blocking access to such websites.

Protect against exploits

An exploit is a type of attack that takes advantage of flaws in a system to breach cybersecurity. It can be challenging to stop.

Visiting websites that are vulnerable to exploits can negatively impact a user’s security. Some web content filters can block access to websites known to be impacted by exploits. Filters can also stop users from accessing websites that share exploit kits.

Protect minors from inappropriate content

Minors don’t have the maturity to safely process content that’s violent, hateful or features pornography. Minors can also be targeted online by online predators and trolls on certain platforms such as social media pages, message boards, and chat rooms. Web content filters can block inappropriate pages that carry adult content or are frequented by people who target minors.

Increase network efficiency

Organizations can improve their network efficiency by using content filters to minimize access to unnecessary web content like social media or entertainment pages. By limiting non-essential traffic, they can optimize their bandwidth and free up resources required for network maintenance.

Web content filters can also shield networks from pages carrying malware like worms that can reduce network efficiency by consuming bandwidth. Similarly, these tools can block websites that cause network stoppages.

Increase productivity

Maintaining productivity in a modern Internet-connected workplace where users have access to social media, online games, streaming websites, and other pages can be challenging. A web content filtering solution with the right settings can reduce distractions and create a more positive work atmosphere by blocking access to this content. It also improves productivity by blocking security threats that can disrupt workflow.

Decrease liability

Governments are encouraging organizations to comply with laws that improve security and privacy and protect data. Web content filtering can help reduce an organization’s liability and comply with regulations by preventing users from accessing websites that can infect systems with privacy-invading malware or expose users to phishing attacks that steal sensitive information.

Blocking access to inappropriate content can also help mitigate the risk of lawsuits from parents or employees exposed to harmful, offensive, or illegal online materials.

How to set up web content filtering policies

Setting up web content filtering policies requires multiple steps. Organizations should begin by identifying their goals and the type of content they want to filter. Next, they should evaluate suitable web filtering solutions and set up the relevant parameters.

For best results, they must test the filtering solution after implementation and address any issues through ongoing monitoring and adjustments. Some tinkering will be necessary to optimize workflow and protection.

Protect students and faculty from dangerous websites and online threats.

Provide safer internet environments for K-12 schools, universities, and education communities. DNS content filtering keeps kids and faculty safe from unwanted online content.


Web content filtering solutions

Deploy remote filters

Remote filtering solutions are different from on-premises filtering solutions because they exist on the cloud. They are usually easier to implement and manage, require fewer resources, and can be scaled with the growth of an organization.

Schedule access

Certain web content filtering solutions allow administrators to set specific times when the filters are active. These solutions can help optimize workflow. For example, a company may still want to allow employees to access online gaming platforms after work hours to play with co-workers and improve camaraderie.

Establish more liberal work policies

Web content filtering solutions can sometimes improve workflow by creating more liberal work policies. The key is to find the right work-life balance. Employers can form a white list of websites and platforms that improve productivity and offer staff more freedom at the workplace.

Communicate internally

Web content filtering can negatively impact a company’s morale or work culture if the implementation is heavy-handed. It’s best to set a clear and easy-to-understand filtering policy and communicate internationally for feedback where employees can offer suggestions for improvement. For example, blocking social media pages may seem like a good idea, but it may hinder the productivity of employees who rely on such platforms for research and marketing.

Category-based filtering

With category-based filtering, filtering solutions can prevent users from accessing certain categories of websites. The technology may use AI algorithms and keyword-matching to scan for certain categories and block content accordingly. Commonly blocked categories include:

  • Pornography
  • Gambling
  • Gaming
  • Social media

Filter URLs

URL filters allow content filtering solutions to block lists of URLs. Such URLs may be linked to scams, phishing, malware, and other kinds of threats. Web content filtering solutions can restrict access to social media websites and their web-based applications with URL filters too.


Reporting solutions for web content filtering may have features such as real-time monitoring, usage reports, threat reports, and others. Network administrators can utilize these features to monitor threats and gain key insights.

Related Articles

Web Content Filtering FAQs

What are the benefits of web content filtering?

Parents, companies, educational bodies, and government organizations typically use web content filtering to secure the privacy and security of users from certain elements of the Internet such as malware, scams, and bad actors like predators. Web content filtering can also raise productivity by reducing access to entertainment or social media pages.

What is the difference between web content filtering and DNS filtering?

While web content filtering and DNS filtering are both web-filtering technologies, they operate at different levels. A web content filter filters Internet content at the application layer. For example, it can stop an Internet browsing application in an operating system from accessing inappropriate content by scanning for unsafe keywords or URLs.

So, what is DNS filtering, and how is it different from web content filtering? As you probably know, the Domain Name System (DNS) is a database that translates domain names into Internet Protocol (IP) addresses, which browsers use to load Internet pages. DNS filtering works by redirecting DNS queries to a different IP address.

DNS filtering can be more effective than web content filtering. While web content filtering offers some control over website access, DNS filtering can block access to a specific or entire category of websites based on their domains on a network level. Web filters react to HTTP/HTTPS traffic, while DNS filters react to DNS queries, which precede HTTP/HTTPS traffic.

Not only can organizations prevent phishing attacks with DNS filtering, but they can prevent a large swath of them. Many organizations also find that DNS filtering is simpler to implement and manage. For example, you can easily configure DNS Filtering rules in OneView using the Rules tab to customize security filtering and allowed domains across your sites and policies.

Why is content filtering controversial?

Critics of content filtering claim the process is similar to censorship because it blocks access to information. They argue that organizations can use web content filtering to control a narrative and even limit freedom of speech and expression. For example, in some countries, schools and governments use content filtering to promote specific political views, ideologies, and religions by limiting access to competing viewpoints.

What is the difference between a content filter and a firewall?

Although a web content filter and a firewall both improve network security, they’re quite different. In a nutshell, a firewall is a network security tool that functions as a traffic controller. It regulates incoming and outgoing network traffic based on a set of pre-defined security rules. For example, it may stop incoming traffic from specific IP addresses known for malicious activity, or it may prevent malicious traffic from leaving a network. 

On the other hand, a web content filter blocks web-based content such as pornography, social media websites, or malicious websites based on its programming to improve productivity, ensure compliance, and protect users.