How Does a Network Block Sites on the Web?

Before answering the question “how does a network block sites on the web”, it may be helpful to some people to explain “why does a network block sites on the web” as there are multiple reasons.

  • A business network may block sites on the web to prevent employees engaging in non-work related online activities.
  • A school network may block sites on the web to comply with state and federal laws relating to harmful Internet content.
  • A WiFi network may block sites to prevent users from viewing inappropriate material in sight of other customers, guests or visitors.

However, the most important reason why any network may block sites on the web is to protect the network – and the users who connect to it – from malware, ransomware and phishing. This reason alone justifies the implementation of a mechanism to block sites on the web, as the cost of recovering from a successful malware, ransomware or phishing attack can be substantial.

So, How Does a Network Block Sites on the Web?

In order to block sites on the web, businesses, school and other organizations providing a WiFi network use a network website filter. This is typically a software-based or cloud-based “virtual appliance” through which all web traffic travels. As web traffic passes through the network website filter, its content is checked to ensure it is malware-free and complies with user policies.

The protection against malware, ransomware and phishing consists of multiple elements. These include blacklists of websites known to harbor malware, antivirus software, malicious URL detection software, and SUBRL filters that check the IP addresses of each website to ensure it is not a known sources of spam emails – the same IP address often being used to deploy ransomware and phishing attacks.

User policies are set by a network administrator. They control what content should be allowed through the network website filter and what should be blocked by the filter. In a business environment, for example, a system administrator may want their network to block sites relating to pornography and online shopping – subjects considered to have the biggest negative impact on workplace productivity.

Setting User Policies with a Network Website Filter

Because user policies will vary significantly according to the nature of the network, the mechanisms for setting user policies have to be versatile. Typically they consist of category filters, keyword filters, and various other tools that control web access by time, by bandwidth or by IP address. A network website filter can also apply different user policies to individual network users or groups of network users.

Category filters are the easiest mechanisms to apply. There are fifty-three categories of website content (abortion, adult entertainment, alternative beliefs, alcohol, etc.) into which more than six billion web pages are sorted. In order for a network to block sites on the web in a certain category, network administrators just click on the name of the category via a web-based management platform.

Keyword filters block access to web pages containing a specific word or phrase, and can be used to prevent users visiting certain types of online content without blocking access to a whole category of content. The other mechanisms for setting user policies with a network website filter are fairly self-explanatory, and each can be applied to one or more user policies with a few clicks of a mouse.

Try a Network Website Filter for Free

SpamTitan´s range of network website filters is the WebTitan range. The WebTitan range has been designed to help administrators of a network block sites quickly and easily without compromising the network´s online security. There are several WebTitan network website filters to choose from:

  • WebTitan Cloud is a universally compatible cloud-based filter that can be integrated with Active Directory for easier management.
  • WebTitan Cloud for WiFi has been specifically designed to protect wireless networks and businesses that promote a BYOD policy.

To find out more about the WebTitan range of network website filters, why not request a free trial today

It takes less than five minutes to find out how does a network block sites on the web, and within twenty minutes you could be protecting your network – and the users that connect to it – from malware, ransomware and phishing attacks.


Could I prevent my customers browsing competitor´s websites?

If customers are using your business´s Wi-Fi network to connect to the Internet, you can prevent them from accessing competitor´s websites via the keyword filtering facility. For example, if you operate a car showroom, you could prevent customers visiting other local car showroom websites to compare the prices of your cars against your competitors.

How do I know prohibited websites are being blocked successfully?

WebTitan filters are equipped with a powerful logging tools that are used to build customizable reports. The reports can tell you which sites were blocked, why they were blocked, and who was trying to access them. It is also possible to set up email alerts for when users attempt to access extremely risky websites, or when the same user persistently attempts to violate acceptable use policies.

Isn’t it possible to circumnavigate a network block site filter with a VPN?

One of the most important category filters on WebTitan’s category list is the anonymizer category, which blocks users taking advantage of website anonymizers, VPNs, and proxy servers in order to circumnavigate acceptable use policies. It is also possible to prevent the use of USB-based portable browsers to ensure acceptable use policies are enforced and eliminate the risk of malware being imported from infected USB drives.

How could a school benefit from applying different user policies to groups of network users?

Schools in receipt of E-rate funding are required to comply with the Children´s Internet Protection Act. In some cases this can result in students being denied access to educationally viable education. SpamTitan´s customizable user policies ensure students can access age-appropriate material while being protected from damaging online content.

Why might I want to apply network web filters by time?

There are multiple scenarios in which it might be appropriate to apply network filters by time. These include businesses who are happy for employees to access social media and personal emails before work, after work and during lunch breaks; hotels who enforce a watershed for viewing certain types of online content in public areas, and sports arenas who want to prohibit in-play gambling.