In the early years of networks, tracking the large amount of information generated (such as usernames, passwords, computer names, printers, personal information, etc.) was an administrative nightmare. Administrators recognized they needed a way to organize and automatically maintain that information in a centralized location. In 1988, X.500 was introduced in response to that need.

X.500 is a depository where information is organized in a hierarchal directory. It allows maintenance and access to information across a network through a Directory Access Protocol (DAP) using the Open Systems Interconnection (OSI) model. By distributing directory access across the network, X.500 allows many separate directories to work together to deliver different types of information or to act as one virtual directory.

In 1993 the International Telecommunications Union (ITU) further enhanced X.500 making it robust and comprehensive including the following features to tackle the information management challenge as outlined in RFC 1308:

• Powerful search capabilities: Users are able to construct arbitrarily complex queries.
• Single global namespace: Users can have a single homogeneous namespace.
• Structured information framework: Defines the information framework used in the directory.
• Standards-based directory services: Enables building of a standards-based directory; applications that require directory information (email, automated resource locators, special-purpose directory tools) can access a planet's worth of information in a uniform manner, no matter where they are.

However, the power of X.500 comes with a price. It is very complex and difficult to implement, for all practical purposes forcing network administrators to only use the parts they absolutely need. Because network administrators were only using a part of X.500 for everyday use, and most desktop computers could not handle the DAP client to access the X.500 services, researchers began to develop a “lighter” version of X.500 that could run on any desktop computer. To accomplish the task researchers only incorporated the X.500 functions that were commonly used, and in 1993 the University of Michigan developed X.500 “light,” which was renamed Lightweight Directory Access Protocol (LDAP).

Netscape developed LDAP further, and the protocol evolved into a more robust system that eventually was adopted by the Internet Engineering Task Force (IETF) as an open standard.

The creation of LDAP lead to other companies, such as Novell and Microsoft, developing their own directory services similar to X.500 “light,” and today there is a mixture of all of the above directory services globally. While the X.500 Directory Access Protocol (DAP) is still used today, LDAP is the overall leader because it is standards-based and easier to implement and manage than X.500. Also, movements such as OpenLDAP are keeping LDAP implementations inexpensive to set up and maintain.