Feature Discovery in Lightweight Directory Access Protocol (LDAP)
obsoleted by
- rfc-4512 — Lightweight Directory Access Protocol (LDAP): Directory Information Models
Extracted elements (11)
Existing LDAP mechanisms for discovering supported versions, controls, extended operations, SASL mechanisms, and subschema are not designed for general feature discovery, motivating the introduction of the 'supportedFeatures' attribute as a general-purpose mechanism.
The 'supportedFeatures' mechanism is intended to complement (not replace) existing LDAP discovery mechanisms for versions, controls, extended operations, SASL, and subschema; it covers elective features not discoverable through those mechanisms.
A client MUST ignore values of 'supportedFeatures' it doesn't recognize, as they refer to elective features the client doesn't implement.
Features associated with non-Standards Track protocol mechanisms SHOULD be registered per BCP 64 procedures.
Features associated with Standards Track protocol mechanisms MUST be registered per BCP 64 (RFC 3383), with 'Feature' placed in the usage field of the submitted LDAP Protocol Mechanism template.
Servers MUST be capable of recognizing the 'supportedFeatures' attribute type by the name 'supportedFeatures'. Servers MAY recognize it by other names.
Each elective feature whose support may be discovered SHALL be identified by an Object Identifier (OID). A server advertises support by providing the OID as a value of the 'supportedFeatures' attribute in the root DSE.
The 'supportedFeatures' attribute type is defined with OID 1.3.6.1.4.1.4203.1.3.5, EQUALITY objectIdentifierMatch, SYNTAX OID (1.3.6.1.4.1.1466.115.121.1.38), and USAGE dSAOperation.
IANA registered the LDAP 'supportedFeatures' descriptor with OID 1.3.6.1.4.1.4203.1.3.5 as an Attribute Type per RFC 3674, assigned by OpenLDAP Foundation under its IANA private enterprise allocation.
This document extends the LDAP Protocol Mechanism registry (RFC 3383) to support registration of values of the 'supportedFeatures' attribute, managed by IANA. A 'Feature' usage in a registration template indicates the value is an LDAP feature.
Since rogue clients can discover server features by other means (such as trial and error), the supportedFeatures discovery mechanism is not believed to introduce any new security risk to LDAP.