LDAP is the acronym for Lightweight Directory Access Protocol. It refers to a software protocol, which enables users to locate individuals, organizations, as well as devices and files in a particular network, whether on an intranet of a corporation or on public internet.

LDAP is not only used for finding contact information and other types of information about individuals, but is also used for encryption certificate lookup, single sign-on option, and many other services in a your network. This software protocol is suitable for any directory type of information where updates are infrequent and quick lookups are common.

LDAP is a lighter version of Directory Access Protocol, which was designed in order to adapt the X.500 to the internet. Because the X.500 is a complex directory system which cannot be supported by desktops and the internet, LDAP was made for public use. The initial version of LDAP does not have security features, making it more lightweight.

This software protocol was made at the University of Michigan and has been recognized by over 40 companies. For instance, Microsoft added LDAP as a part of the Active Directory in its products such as the Outlook Express. Furthermore, Netscape also incorporated LDAP in its Communicator suite and the products of Cisco that are used for networking also support this application protocol.

There are three levels of LDAP servers including huge public servers, organizational servers such as in corporations and universities, and small servers used for workgroups. An LDAP directory can be shared among various servers and each one will have a replicated copy of the directory, which is also synchronized regularly. When an LDAP server, also known as a Directory System Agent, receives a request, it will be responsible for it and may pass it to another Directory System Agent if needed provided that a single response will be delivered to the user.