LDAP
Lightweight Directory Access Protocol
In computer networking, the Lightweight Directory Access Protocol, or LDAP ("ell-dap"), is a networking protocol for querying and modifying directory services running over [ http://en.wikipedia.org/wiki/Internet_protocol_suite TCP/IP]. An LDAP directory usually follows the wikipedia:X.500 model: it is a tree of entries, each of which consists of a set of named attributes with values. While some services use a more complicated "forest" model, the vast majority use a simple starting point for their database organization.
An LDAP directory often reflects various political, geographic, and/or organizational boundaries, depending on the model chosen. LDAP deployments today tend to use wikipedia:Domain Name System (DNS) names for structuring the most simple levels of the hierarchy. Further into the directory might appear entries representing people, organizational units, printers, documents, groups of people or anything else which represents a given tree entry, or multiple entries.
Its current version is LDAPv3. LDAPv3 is specified in a series of wikipedia:IETF Standard Track RFCs as detailed in RFC 4510.
