DNSfilters
DNSfilters are a type of network security tool that leverages the Domain Name System (DNS) to block access to malicious or unwanted websites. Instead of inspecting the actual content of web traffic, DNSfilters operate by intercepting DNS queries. When a user attempts to access a website, their device sends a DNS query to resolve the website's domain name (e.g., google.com) into an IP address. A DNSfilter service maintains a database of known malicious or prohibited domains. If the queried domain is found in this database, the DNSfilter prevents the resolution by returning a false IP address or no address at all, effectively blocking access to the website.
These filters are commonly used for various purposes, including parental controls to restrict children's access to