udp nat

s.py

import socket

UDPSock = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)

listen_addr = ("", 3386)
UDPSock.bind(listen_addr)

ips = []

while True:
    data,addr = UDPSock.recvfrom(1024)
    print addr , 'is connected.'
    ips.append(str(addr[0]) + ':' + str(addr[1]))
    if(len(ips) == 2):
        dest = ''
        for ip in ips:
            for i in ips:
                if ip != i:
                    dest = i
                    UDPSock.sendto(dest, (ip.split(':')[0],int(ip.split(':')[1])))