Communication between different entities in a network is based on Python's classic concept of sockets. A socket is defined by the IP address of the machine, the port on which it listens, and the protocol it uses.

Creating a socket in Python it is done through the socket.socket() method. The general syntax of the socket method is as follows:

s = socket.socket (socket_family, socket_type, protocol=0)

These arguments represent the address families and the protocol of the transport layer.

Depending on socket type, sockets are classified into flow sockets (socket.SOCK_STREAM) or datagram sockets (socket.SOCK_DGRAM), based on whether the service uses TCP or UDP. socket.SOCK_DGRAM is used for UDP communications, and socket.SOCK_STREAM for TCP connections.

Sockets can also be classified according to the family. We have UNIX sockets (socket.AF_UNIX) which were created before the concept of networks and are based on files, the socket.AF_INET socket which is the one that interests us, the socket.AF_INET6 for IPv6 socket, and so on: