IPv6 is short for "Internet Protocol version 6". IPv6 is the Internet's next-generation protocol, designed to replace the current Internet Protocol, (IP) version 4. In order to communicate over the Internet, computers and other devices must have sender and receiver addresses. These numeric addresses are known as Internet Protocol addresses. As the Internet and the number of people using it grows exponentially, so does the need for IP addresses. This paper gives a complete overview of IPv6 addressing and shows the comparison with IPv4.