Version 4 (IPv4) is the dominant protocol used on the Internet to route network traffic. A successor protocol called IPv6 has been defined and is gradually being adopted. IPv4 is a connectionless protocol and works on packet switched networks. Each network node on an IPv4 network has to have a unique IP address. This allows routing of traffic to the correct target node from anywhere on the Internet. In practice most end user computing devices located within organisations will use a shared IP address space and the network border infrastructure will perform Network Address Translation (NAT) using a few public IP address for network requests to the Internet.