Understanding TCP Packets

If you use TCP on Python, you usually create sockets with socket.socket(socket.AF_INET, socket.SOCK_STREAM), but you cannot set or retrieve the flags ACK, SYN, PSH to automatically process TCP connections.

If you want to set and retrieve the flags ACK, SYN, PSH, use the RAW socket by setting the parameter socket.SOCK_RAW.In this case, you can configure and retrieve the TCP and IP headers yourself.

s=socket.socket(socket.AF_INET, socket.SOCK_RAW)

The PSH(push) flag is a flag that requires that data received be handed over to the application immediately when turned on, but it is not normally used because TCP is implemented even when turned off.

Home stackoverflow: How does TCP PSH work?