Lightweight Directory Access Protocol
The Lightweight Directory Access Protocol (LDAP) is a standard method by which application clients can query and access information stored on directory servers over TCP/IP connections. Typically, a published directory contains data about people or other entities that users can access. The most common examples of paper-based directories are the yellow and white pages of telephone books, which enable a customer to look up the telephone number for a person or company. An example of an electronic directory is a published e-mail address book, which enables an e-mail user to look up a person's e-mail address and other details, such as office location and internal phone extension.
LDAP is derived from the X.500 global directory and the Directory Access Protocol (DAP), a complex access protocol for performing a wide variety of directory functions. LDAP is a lightweight offspring of DAP, shedding the unnecessary features of client-server access scenarios. The result of the weight loss is LDAP, a protocol that greatly simplifies implementation, reduces software complexity, improves performance, and in the process, encourages wider adoption.