IPv4 (Internet Protocol version 4) is the most widely used addressing system on the internet. It uses 32-bit addresses written in dotted decimal notation — like CleanBrowsing's free resolver at 185.228.168.168.
IPv4 is the fourth version of the Internet Protocol and the first to be widely deployed. It assigns a unique 32-bit IP address to every device on a network, enabling data to be routed between billions of devices worldwide.
IPv4 addresses are written in dotted decimal notation — four numbers (0–255) separated by dots. For example, CleanBrowsing's Family Filter resolver is 185.228.168.168.
Despite the growth of IPv6, IPv4 remains the dominant protocol on the internet and is used by most DNS configurations.
IPv4 addresses are divided into different classes and ranges:
127.0.0.1 (localhost) — refers to the device itselfWith 4.3 billion addresses and billions of connected devices, the available IPv4 address pool has been exhausted. Regional Internet Registries (RIRs) have run out of new IPv4 blocks to allocate.
Technologies like NAT and CGNAT extend IPv4's life by allowing multiple devices to share a single public IP. However, IPv6 is the long-term solution with its virtually unlimited address space.
CGNAT can complicate DNS filtering because multiple customers share one public IP, making it harder to associate individual filter profiles with specific users.
CleanBrowsing's free DNS resolvers use IPv4 addresses:
185.228.168.168 / 185.228.169.168185.228.168.10 / 185.228.169.11185.228.168.9 / 185.228.169.9These addresses are configured in your router's DHCP settings or directly on individual devices. For the IPv6 equivalents, see our filters page.
On the authoritative DNS side, IPv4 A records map domain names to server addresses. Services like NOC.org manage these records for domain owners, while CleanBrowsing's recursive resolver handles the lookup and filtering for end users.