We are trying to diagnose a chronic disconnection issue. Overnight, nearly every night, our HTTP long poll client is disconnected from the server. The most likely proximate cause is that the longpoll wasn't received within 35s of the last one.
That proximate cause doesn't help us very much because it doesn't explain why.
Claim: some network device in the path between the clients and the server is dropping or delaying packets.
Question: How would we go about finding evidence for or against this claim?
The clients are on the West Coast of North America and the server is in the East so there's a fair bit that might fail. I'm not sure how to decide if this failure is in the network or not.
The server is Centos. The clients are Ubuntu and Windows.