Reviewer: Dan Romascanu Review result: Ready This document targets Informational status. It is Ready from an OPS-DIR perspective and it offers valuable information for operators deploying TLS. It does not define a new protocol, thus a full RFC 5706 OPS-DIR review does not apply. It does however raise a number of operational issues in the deployment of multiplexed servers that rely on the Service Name Information (SNI) TLS extension which is a protocol element transmitted in clear text. Section 3 details the different type of attacks and lists encryption requirements for SNI that would prevent these, but notes that not all can be simultaneously met by implementations and deployments. Section 4 describes the HTTP Co-Tenancy Fronting as a solution that could be deployed in the absence of TLS-level SNI encryption. The HTTP fronting solution can be deployed without modification to the TLS protocol, and does not require using any specific version of TLS. There are however a few issues regarding discovery, client implementations, trust, and applicability which are further discussed. Operators should note that Section 5 states that 'The current HTTP based solutions described in Section 4 only meet some of these requirements. In practice, it may well be that no solution can meet every requirement, and that practical solutions will have to make some compromises.'
