The Best Open Source Web Filters Solutions

In the internet age, content is gold. Therefore, it must be protected from outside interference. 

To do this, there are tools that can filter web content. Such tools block access to the content of certain websites and can filter out offensive, inappropriate, and unethical content. 

Filtering can be done via hardware and software solutions. To do this, rules are set, and certain types of sites cannot be visited.

This article will talk about open source web filters solutions that will suit absolutely everyone.

Learn more about web security here.

What is web filtering?

Web filtering is the filtering of certain content contained on websites on the internet. It’s no secret that at the moment there are a huge number of websites with every imaginable kind of content on the internet.

Opensource content filter

This can be a problem even for a small office. It isn’t easy to track what an employee does during working hours. Of course, most likely employees will be engaged in work — at least most of the time. 

However, an employee can sometimes engage in personal business during work time — communicating on social networks or making purchases through online stores. This is quite undesirable for businesses as it slows down the workflow. But this is not the worst-case scenario. Employees may visit websites prohibited by law through the organization’s network, exposing the company to legal trouble.

How can you protect your data on social media? Here is the guide.

Why should you use web filtering tools?

Web filtering tools prevent visits to dangerous sites that host malware or are classified as phishing sites. But their main task is to manage access to websites of certain categories. 

With their help, you can easily restrict company employees’ access to all websites of certain categories. All incoming traffic is analyzed and categorized. Depending on the settings of the internet filtering tool, access to certain categories of content may be blocked, and a warning will be displayed to the user.

In addition to content filtering of HTTP traffic, developers of web filtering systems provide their users with the opportunity to check secure HTTPs traffic and the reliability of SSL certificates. This is relevant when attackers use encryption to steal personal data, bank card numbers, and PIN codes.

Advantages of opensource content filter measures:

  • Protecting children from unwanted content.
  • Ensuring control and monitoring.
  • Protection against malware.
  • Ensuring high productivity in the workplace.
  • Improving network security.
  • Increasing network bandwidth.

You can read more about bandwidth here.

How does web filtering work?

Web filtering works quite simply. After establishing a TCP connection, the client requests the server to access the website using an HTTP request. 

The server provides access to the site using an HTTP response. Here a web filter comes into play. It contains so-called regular expressions. The web filter searches for these regular expressions in the response from the webserver. 

Opensource web filtering

If a match is found, the corresponding action is selected. Regular expressions allow you to control blocking and access to websites very flexibly. They can consist of various prohibited phrases and hostnames or URLs that need to be blocked.

The list of open source web filters solutions

Open-Source Filter

Open-Source Filter is also known as a content filter. This tool uses blacklists and word association algorithms to identify authentic and suitable websites. 

This tool is widely used to ensure compliance with a company’s policy and compliance with all regulatory requirements, for example, CIPA.  

It is free and works with the Clear OS system. The latest implemented version works with the standard GPL license and other additional features.


OpenDNS is an opensource web filtering solution that provides domain name system resolution services. It functions in conjunction with DNS servers and various cloud computing security features. It is designed to protect the vulnerabilities of companies.

In 2015, the tool was sold to Cisco, after which the name was changed to Cisco Umbrella. However, the products still remained working under the name OpenDNS. This was done to preserve the value and trust of users.

A couple of years ago, Cisco talked about the upcoming technical cooperation with FireEye. It has added OpenDNS features and now protects remote employees and branches.


SquidGuard is a URL redirector that uses the proxy software Squid with blacklists. This is a great solution for filtering open source web content. In addition, the solution was recently registered under the GNU public license.

SquardGuard is a free tool that provides customizable logging for progress indicators when compiling blacklists.

It is possible to rewrite compliance instructions and block URLs and certain hostnames. It also provides authentication over MySQL databases and corrects any errors in the system.


DansGuardian allows you to block a site by the requested URL/domain and based on the keywords contained on the page itself. Each keyword can be assigned a weight, and if, for example, a page scores more than 100 points, it will be blocked. 

As befits a filter, DansGuardian can pass traffic to white sites, prohibit file extensions from downloading, and much more.

DansGuardian works with Unix, Linux, Windows, and Macintosh computers. It is highly recommended for schools, businesses, internet service providers, etc.

Comodo Dome Shield

Comodo Dome Shield is a cloud DNS security solution that allows protection against web-based attacks and domain filtering.

The tool helps organizations inform employees about the threats of web surfing. In addition, it provides information to ensure data security and maintain professional integrity.

Comodo Dome Shield protects your device from all advanced threats no matter where you connect to the internet from. The web security provided with Dome Shield will work seamlessly across 2G, 3G, 4G, LTE cellular networks, and Wi-Fi.

Wi-Fi protection is essential right now. In the article, you can find some ways to protect yourself.

Final word

Content filtering is an essential part of protecting your network. Visiting questionable websites on the internet can lead to the appearance of viruses and malware on your computer (or on the network) which can cause severe disruption. 

Alternatively, you may just want to filter the content so that family members or friends cannot receive inappropriate content while they are on your home network.


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