Simple TCP Server

[nilamo]

    def run(self):
        while 1:
            print('Client sent:', self.sock.recv(1024).decode())
            self.sock.send(msg)

self.sock.close()?

If you're doing anything more than just messing around, you should probably use something designed for being fast at a low level, like Twisted (http://twistedmatrix.com/trac/)