Businesses and other organizations use content filtering to block employees or customers from accessing certain online content. 

There are a few reasons they may do this:

  • To improve the security of office networks
  • To prevent customers, students at educational institutions, or anyone who uses a public WiFi hotspot from accessing illegal or undesirable content
  • To improve productivity among staff members by restricting access to social media

In this article, we’ll dig deeper into why organizations use content filtering and how they implement it. 

Why use content filtering?

A business or organization may implement content filtering for a number of reasons. It’s commonly employed to enforce policies related to acceptable use, security, and compliance in various contexts, such as homes, schools, workplaces, and public networks.


Content filtering helps to protect networks and systems from malware, viruses, and other security threats by blocking access to malicious websites and content. It can prevent employees from inadvertently downloading or accessing harmful files, and also protect them from phishing scams(new window).

Acceptable Use

Many (if not most) organizations have acceptable use policies (AUPs) that govern how their network and internet resources can be used. For example, most companies don’t want staff using their office WiFi networks to access NSFW(new window), offensive, discriminatory, or harassing  content.

Content filtering can enforce these policies by blocking access to websites and content that violate the AUP.

Public WiFi

Similarly, businesses that offer public WiFi services, such as cafés, airports, and hotels, use content filtering to ensure the security and safety of their customers, while preventing access to illegal or harmful content.

This is also true of universities, schools, and other educational establishments, which often impose stricter restrictions on their networks than commercial businesses do.  

Increased productivity

Organizations sometimes use content filtering to increase workplace productivity by restricting access to non-work-related websites, such as social media, gaming, and streaming platforms. 

The aim is to help ensure that employees stay focused on their tasks, but when everyone can trivially access such services on their smartphones, it’s questionable how effective such tactics are. 


Businesses often use content filtering to ensure they adhere to industry regulations, legal requirements, and internal policies. This can include complying with data protection regulations such as HIPAA(new window), GDPR(new window), or CCPA(new window) by blocking staff from sharing sensitive information via email or other communication channels.

Content filtering can also be used to help ensure compliance with industry-specific regulations. For example, a financial institution might be subject to regulations such as the Sarbanes-Oxley Act (new window)or the Payment Card Industry Data Security Standard(new window) (PCI DSS), which require strict controls on data access and storage. Content filtering can help enforce these regulations.

Another aspect of compliance is record keeping and auditing. Content filtering solutions may provide logs and reports that can be used for auditing and compliance verification. These records can be critical for demonstrating that an organization is taking the necessary steps to meet its compliance obligations.

Bandwidth management

Content filtering can be used to manage network bandwidth more efficiently by prioritizing business-critical applications and limiting access to bandwidth-intensive activities such as video streaming.

How does content filtering work?

Content filtering can be implemented in various ways. The exact method used will depend on an organization’s needs (and it may use multiple content filtering techniques).

DNS filtering

The Domain Name System (DNS) maps human-readable domain names to their corresponding IP addresses(new window) (for example: to DNS filtering prevents DNS queries for blacklisted domains from being resolved. 

Learn more about how DNS works

In addition to web content filtering, DNS filtering can help protect organizations from malware and phishing threats by blocking access to known malicious domains. It can prevent users from inadvertently visiting websites that distribute malware or host phishing scams.

DNS filtering can also be used to block access to ad servers or domains known for delivering online advertisements. This helps reduce the number of ads displayed when browsing the web, thus providing a better experience for users.

Proton VPN offers a DNS filtering tool on all platforms called NetShield Ad-blocker that can block ads, malware, and trackers.

Learn more about NetShield Ad-blocker 

URL filtering

URL filtering is similar to DNS filtering, except that it blocks content based on its web address. This allows more fine-grained control than DNS filtering, as it can be used to block specific pages on a website, rather than the entire website. However, it’s less useful for blocking other content, such as malware and ads. 

Keyword filtering

Filtering content based on specific words or phrases is useful for blocking access to particular types or categories of websites, such as those which host gambling or adult content.


Some organizations block access to all web content that can be accessed using company resources except for a predetermined list of “whitelisted” websites. This is usually done for security reasons. 

Content analysis

This is a fairly new type of content filtering that uses machine learning (AI) algorithms, such as natural language processing and image and video recognition, to analyze the content of websites and then implement blocks based on that analysis. 

Content analysis allows for much more nuanced content filtering than the traditional whitelist/blacklist approach. For example, AI content analysis filtering could tell the difference between an adult website and a website that offers sexual health advice.

However, there are numerous privacy and ethical concerns related to AI content analysis. These can be addressed with effective and responsible human oversight, but achieving the right balance between automated content analysis and human judgment remains a challenging issue. 

Other reasons for content filtering

Although the focus of this article is on organizations, such as businesses and educational facilities that use content filtering, it’s worth noting that content filtering is also used in other contexts.

Government censorship

Authoritarian governments around the world block their citizens’ access to content for political, social, or social religious reasons. As well as the kinds of content filtering listed above (often as the ISP level), governments use their power to execute additional types of content filtering.

Search engine blocks — Governments can pressure search engine providers to remove content they object to from search results.

Deep packet inspection (DPI)  — This is a method of examining data packets that pass through a network so that the traffic type can be identified. 

Parental control

A popular use of content filtering is by parents who wish to moderate what their children can access on the internet. Although traditionally performed by “net nanny” software, over recent years there has been a major shift toward using online software as a services(new window) (SaaS) solutions for this purpose. 

Final thoughts

There are many good reasons for organizations to perform content filtering. Moving forward, it’s likely that artificial intelligence will play an increasingly important role in this, so it’s important for companies to develop effective and ethical ways to safeguard the privacy of their staff, customers, or students. 

There is also the risk that authoritarian governments will abuse this power to restrict their citizens’ freedom. However, with Proton VPN for Business, you can evade such restrictions, allowing your organization’s staff unhindered to access the free and open internet. 

Learn more about how your business can benefit from using a VPN
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