linux-nc-and-python-sockets


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linux-nc-and-python-sockets

nc or netcat lets you create socket servers or connect to services via
sockets.

The nc man page is excellent. This first thing I tried was creating a
simple-chat like program between two terminals.

Simple nc chat application

Start listening (nc -l) for a connection on a port (31337).

On terminal A

    nc -l 31337

Connect to (127.0.0.1) on a port (31337).

On terminal B

    nc 127.0.0.1 31337

Like the man page suggests all text submitted on either terminal A or B
will appear on both terminals. Conventionally the server "listening" for
connections is typically labeled the server. In this case neither
terminal is a server because if either closes, both close...

Use python to interact with nc

On terminal A

    nc -l 31337

On terminal b

    python

    >>> import socket
    >>> s = socket.socket( socket.AF_INET, socket.SOCK_STREAM )
    >>> s.connect( ( 'localhost', 31337 ) )
    >>> s.send( 'python says hello nc' )
    20
    >>> s.recv( 30 )
    'nc says hello python\n'
    >>> # To learn more about sockets do:
    >>> help( s )
    >>> # when you are finished run s.close()

The constant socket.AF_INET creates a socket which allows us to connect
to an ip/name and port. The constant socket.AF_UNIX creates a socket
which allows us to connect via files? socket.SOCK_STREAM is the type of
socket (tcp/ip). socket.SOCK_DGRAM (data-gram or UDP)

------------------------------------------------------------------------

Source:
https://foxhop.net/f3b9a5c5-2f95-11f1-beb3-e86a64d24d78/linux-nc-and-python-sockets
Snapshot: 2026-06-15T11:35:23Z
Generator: Remarkbox 50b9d1e