You are clogging your TCP stack with outgoing data and all the connection establishment and termination packets.
If you have to stick to this design, then force each connection to linger until its data has been successfully sent. That is to say, that by default, close()
on the socket returns immediately and further delivery attempts and connection tear-down happen "in the background". You can see that doing so over 20000+ times in a tight loop can easily overwhelm the OS network stack.
The following will force your socket close()
to hang on for up to 10 seconds trying to deliver the data:
import struct
s.setsockopt(socket.SOL_SOCKET, socket.SO_LINGER, struct.pack('ii', 1, 10))
Note that this is not the same as Python socket.sendall()
- that one just passes all the bytes to the kernel .
Hope this helps.