As the scale and proliferation of distributed applications continues to increase a need often arises to track the availability of entities that comprise the distributed system. An entity that is part of such a distributed system could be a resource, a service that provides a set of exposed capabilities, an application or a user. In this paper we present a transport-independent scheme for tracking the availability of entities in distributed systems. The scheme enforces the authorized generation and consumption of traces (encapsulating entity availability). The scheme also facilitates the secure distribution of traces while coping with some classes of denial of service attacks.