Sockets

import socket

host = 'localhost' # empty string to listen on all interfaces, or 'localhost', or an external IP/hostname
port = 12345
listener = socket.socket()
listener.bind((host, port))
listener.listen(4) # the number of connections to queue.  You often can't raise this higher than 5

while True:
    try:
        conn, addr = listener.accept()
        buffer = conn.recv(4092) # maximum size to receive, in bytes
        conn.close()
    except IOError:
        # if it times out (receives no data), we want it to just try again next time
        pass
    if buffer:
        pass
        # you'll probably want to put something here

listener.close() # clean it up when we're finished