Lightweight Directory Access Protocol (LDAP) is an Internet protocol that enables users with LDAP clients to access directory information from the Microsoft Exchange Server directory. Clients with permission to use LDAP can browse, read, search, and write directory listings in the Microsoft Exchange Server directory. For example, a user can search for specific information, such as phone numbers and office locations, from any application that supports LDAP. Many LDAP clients can access a single Microsoft Exchange Server computer and perform queries for directory information such as user names and locations. With the appropriate permissions, you can modify Microsoft Exchange Server directory information with LDAP. For example, a user can use an LDAP application to modify his or her address or phone number.