import socket
import stun

nat_type, external_ip, external_port = stun.get_ip_info()

print(nat_type)
print(external_ip)
print(external_port)

sock = socket.socket()
sock.bind((local_host, external_port))

sock.listen(1)
conn, addr = sock.accept()

print('connected:', addr) 

while True:
    data = conn.recv(1024)
    if not data:
        break
    conn.send(data.upper())

conn.close()

import socket

sock = socket.socket()
sock.connect((extIP, extPORT))
sock.send(b'hello, world!')

data = sock.recv(1024)
print(data)
sock.close()

Traceback (most recent call last):
  File "client.py", line 4, in <module>
    sock.connect((XXX.XXX.XXX.XXX, PPPP))
ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it