1. Introduction

LDAP is the Lightweight Directory Access Protocol [RFC4510]. This document specifies the LDAP URL format for version 3 of LDAP and clarifies how LDAP URLs are resolved. This document also defines an extension mechanism for LDAP URLs. This mechanism may be used to provide access to new LDAP extensions.

Note that not all the parameters of the LDAP search operation described in [RFC4511] can be expressed using the format defined in this document. Note also that URLs may be used to represent reference knowledge, including that for non-search operations.

This document is an integral part of the LDAP technical specification [RFC4510], which obsoletes the previously defined LDAP technical specification, RFC 3377, in its entirety.

This document replaces RFC 2255. See Appendix A for a list of changes relative to RFC 2255.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119].