I have the idle timeout set to 20 minutes. However, tests with a Python TCP client talking to a a Python TCP server using "epoll", give me an issue when the idle time is roughly 5 minutes of inactivity. I loose the last packet sent, and get an error thrown from the client when after 10 minutes it tries to close the connection, as follows:-
Traceback (most recent call last):
File "atlas_client.py", line 121, in <module>
make_connection()
File "atlas_client.py", line 111, in make_connection
skt.shutdown(socket.SHUT_RDWR)
OSError: [Errno 107] Transport endpoint is not connected
Running this test locally on my Ubuntu VM, gives no such issue.
I am a bit of a loss as to what to try. I can (I believe) force keep-alive packets, however on a 4g connection when we are paying for each and every byte sent/received I don't really want to do this.
How can I tell whether this is an Azure firewall issue, Ubuntu VM or a problem with my code?