Hi all,

The WebSocket protocol specification (RFC 6455) defines a _protocol_level_ keep alive fonctionnality (the protocol defines both a 'ping' and a 'pong' frame).

Unfortunately, it seems that nginx doesn't take these frames into account to reset its timeout watchdog timer so far... so that you have to implement some _application_level_ heartbeat mecanism if you don't want your WebSocket connection be broken by an intermediate nginx on low activity periods...

This is ennoying: such application work has a quite heavy resource cost, especially on the server side. This looses some of the most valuable benefits of a WebSocket connection: maintaining an active asynchronous notification channel from the server to the client, just in case...

Hope this helps,
Philippe.