import socket

# DZIAŁA OK - PUBLIC -> PUBLIC
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind(('192.168.200.15', 7777))
s.sendto('test'.encode(),('192.168.200.16', 10000))

# DZIAŁA OK - LOOPBACK -> LOOPBACK
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind(('127.0.0.1', 7777))
s.sendto('test'.encode(),('127.0.0.1', 10000))

# DZIAŁA OK - PUBLIC -> LOOPBACK
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind(('192.168.200.15', 7777))
s.sendto('test'.encode(),('127.0.0.1', 10000))

# BŁĄD - LOOPBACK -> PUBLIC
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.bind(('127.0.0.1', 7777))
s.sendto('test'.encode(),('192.168.200.16', 10000))
# WYNIK:
# Traceback (most recent call last):
# File "x.py", line 21, in <module>
# s.sendto('test'.encode(),('192.168.200.16', 10000))
#OSError: [Errno 22] Invalid argument