What Are VPNs?

Virtual Private Networks (VPNs) are tools designed to create encrypted tunnels for secure internet access. They are widely used by businesses to allow employees to connect to corporate networks remotely and by individuals seeking greater privacy online. A VPN wraps all communication inside a secure wrapper, making the traffic invisible to anyone monitoring the network.

How VPNs Interact with Content Filtering

While VPNs are legitimate security tools, they can interfere with content filtering effectiveness. When a VPN is active, it encrypts all traffic between the user's device and the VPN server. This means that DNS-based content filters cannot inspect the traffic to determine which websites are being accessed, effectively allowing users to bypass filtering restrictions entirely.

This is a significant concern for parents, schools, and organizations that rely on content filtering to maintain safe browsing environments. If a user connects to a VPN, the content filter becomes blind to their activity.

Content Filtering Compatibility

Whether a VPN supports content filtering depends on the specific service. Work VPNs typically do not allow DNS configuration changes since the organization manages all network settings. Consumer VPNs, on the other hand, offer more flexibility.

Some consumer VPN providers like ProtonVPN and NordVPN allow users to configure custom DNS settings, which means you can potentially use CleanBrowsing's DNS servers while connected. However, success varies by provider and depends on whether a public IP address is available.

Blocking VPNs

Administrators who want to maintain content filtering effectiveness may need to restrict VPN usage on their networks. CleanBrowsing offers resources for blocking VPN access through a combination of content filtering and router controls.

The approach involves blocking known VPN domains and protocols at the DNS and router level. While it is not possible to block every VPN service, restricting the most popular ones significantly reduces the likelihood of users bypassing your filters.

Other Bypass Methods

VPNs are not the only way users can bypass content filtering. Browser extensions can also function as gateways to the outside world, providing VPN-like capabilities without requiring a separate application. Understanding these various bypass methods is essential for maintaining effective content filtering across your network.