New and emerging P2P applications require sophisticated range query capability and also have strict requirements on query correctness, system availability and item availability. While there has been recent work on developing new P2P range indices, none of these indices guarantee correctness and availability. In this paper, we develop new techniques that can provably guarantee the correctness and availability of P2P range indices. We develop our techniques in the context of a general P2P indexing framework that can be instantiated with most P2P index structures from the literature. As a specific instantiation, we implement P-Ring, an existing P2P range index, and show how it can be extended to guarantee correctness and availability. We also quantitatively evaluate our techniques using a real distributed implementation.