A first network packet directed from one VPN endpoint to a second VPN endpoint is received at an intermediary network processing component. Metadata indicating that the first network packet is a candidate for monitoring is stored. In response to determining that a second packet received at the intermediary comprises an acknowledgement to the first packet, a traffic quality metric is stored at a location accessible to a VPN traffic analyzer. The VPN traffic analyzer responses to a traffic quality query using the metrics collected at the intermediary.