This document describes authentication methods and security mechanisms of the Lightweight Directory Access Protocol (LDAP). This document details establishment of Transport Layer Security (TLS) using the StartTLS operation. This document details the simple Bind authentication method including anonymous@ unauthenticated@ and name/password mechanisms and the Simple Authentication and Security Layer (SASL) Bind authentication method including the EXTERNAL mechanism. This document discusses various authentication and authorization states through which a session to an LDAP server may pass and the actions that trigger these state changes. This document@ together with other documents in the LDAP Technical Specification (see Section 1 of the specification's road map)@ obsoletes RFC 2251@ RFC 2829@ and RFC 2830.