Exinda ExOS documentation mentions Flow is several places. This article explains what a flow is.
A flow is basically all packets involved in a conversation with the same IPs and the same TCP or UDP ports.
The flow will be something like:
- All packets are between 10.0.0.10 and 10.0.0.20 where 10.0.0.10 is listening on TCP port 50,000 (Client) and 10.0.0.20 is listening on port 443 (Server listening HTTPS).
- A TCP flow starts with a tcp_syn packet from the client and ends with a tcp_rst or a tcp_fin from the server.
So if there are random packets flowing through with the criteria above, then the flow is still considered to be running.