import socket

s = socket.socket ()
host = socket.gethostbyname('localhost')
port = 64432
s.bind((host,port))
s.listen()


(connection, addr) = s.accept()
msg = 'test'
while msg != 'STOP':
    print('verbindung von ', addr)
    bytes = connection.recv(4096)
    msg = bytes.decode('utf-8')
    msg = msg.upper()
    connection.send(msg.encode('utf-8'))
else:
    connection.close()