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The socket is a powerful abstraction as it allows processes to communicate even if they are located on different computers. In this specific cases, the inter-processes communication will go through a network.
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This function is now using the ``recvfrom`` system call that will also provide the address of the peer who sent the message. As addresses are generic and can have different sizes, ``recvfrom`` also tells us the size of the address that it has written.
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This system call will assign the socket ``sockfd`` to the ``addr`` remote socket address. The process can then use the ``send`` and ``write`` system calls that do not to specify the destination socket address. Furthermore, the calls to ``recv`` and ``read`` will only deliver messages sent by this remote address. This is useful when we only care about the other peer messages.
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Until now, we learned how to use sockets that were already created. When writing a whole program, you will have to create you own sockets and choose the concrete technology that it will use to communicate with others. In this section, we will create new sockets and allow a program to communicate with processes located on another computer using a network. The most recent standardized technology used to communicate through a network is the :term:`IPv6` network protocol. In the IPv6 protocol, hosts are identified using *IPv6 addresses*. Modern operating systems allow IPv6 network communications between programs to be done using the socket API, just as we did in the previous sections.
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Using sockets for inter-process communication
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Using this code, the program will read and print an arbitrary message received from an arbitrary peer who knows the program's socket address. If we want to know the address of the peer that sent us the message, we can use the ``recvfrom`` system call. This is what a modified version of ``bind_and_receive_from_peer`` is doing below.
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