The IPv6 echo server first determines its IPv6 information by calling socket.getaddrinfo(). Notice that we passed the AF_UNSPEC protocol for creating a TCP socket. The resulting information is a tuple of five values. We use three of them, address family, socket type, and protocol, to create a server socket. Then, this socket is bound with the socket address from the previous tuple. It then listens to the incoming connections and accepts them. After a connection is made, it receives data from the client and echoes it back.

On the client-side code, we create an IPv6-compliant client socket instance and send the data using the send() method of that instance. When the data is echoed back, the recv() method is used to get it back.