Re: How should “tcpip_tcp_client_server” be modified for getting JST?
You need to be able to capture the traffic between your board and the NTP server. For this you need a switch with a mirroring port, or a network sniffer, etc.
The log for the communication between your PC and the NTP server could serve as a model, to see what's going on.
When you get that capture, please attach the wireshark capture file, I cannot see the details in a text file.