I have a TCP server running on a PC that accepts the connection from the XBee module and receives the first IPv4 TX message. The XBee module receives the IPv4 RX response from the PC correctly. The next time I send an IPv4 TX message from the XBee module, I would like to use a valid Source Port for the connection. The Destination port value received in the IPv4 RX message does not seem to work. Only a zero in the IPv4 TX Source Port, which creates a new connection, seems to work. Any help is appreciated.