Mitigation of Unsolicited Traffic across Domains with Host Identities and Puzzles

Abstract

Abstract. In this paper, we present a general host identity-based technique for mitigating unsolicited traffic across different domains. We propose to tackle unwanted traffic by using a cross-layer technique based on the Host Identity Protocol (HIP). HIP authenticates traffic between two communicating end-points and its computational puzzle introduces a cost to misbehaving hosts. We present a theoretical framework for investigating scalability and effectiveness of the proposal, and also describe practical experiences with a HIP implementation. We focus on email spam prevention as our use case and how to integrate HIP into SMTP server software. The analytical investigation indicates that this mechanism may be used to effectively throttle spam by selecting a reasonably complex puzzle.