In one embodiment, an endpoint elicits a pattern of STUN responses to identify security devices located on a call path. The endpoint then uses address information from the identified security devices to establish an efficient media flow with a remote endpoint. The endpoint can optimize the number of network devices and network paths that process the endpoint's keepalive message. Additionally, the endpoint may request custom inactivity timeouts with each of the identified security devices for reducing bandwidth consumed by keepalive traffic.