Abstract. The Reliable Server Pooling (RSerPool) architecture is the IETF's novel approach to standardize a light-weight protocol framework for server redundancy and session failover. It combines ideas from different research areas into a single, resource-efficient and unified architecture. While there have already been a number of contributions on the performance of RSerPool for its main tasks -pool management, load distribution and failover handling -the robustness of the protocol framework has not yet been evaluated against intentional attacks.The first goal of this paper is to provide a robustness analysis. In particular, we would like to outline the attack bandwidth necessary for a significant impact on the service. Furthermore, we present and evaluate our countermeasure approach to significantly reduce the impact of attacks.