LDAP

Lightweight Directory Access Protocol
LDAP is the Lightweight Directory Access protocol. It's standards-based protocol that sits on top of TCP/IP and allows clients to perform a variety of operations in a directory server, including storing and retrieving data matching a given set of criteria, authenticating clients, and more. The standard TCP ports for LDAP are 389 for unencrypted communication and 636 for LDAP over TLS-encrypted channel, although it's not uncommon for LDAP servers to listen on alternate ports for variety of reasons.
LDAP is a protocol for reading and writing directories over an IP network, If you need to update or modify things in an AD you would be using LDAP, it is used in Windows Active Directory, Apple OpenDirectory, Novell eDirectory.
It uses a standard called X.500 it was written to interact with different telephone directories, it does this by using distinguished names.
  • CN = Common Name
  • OU = Organizational Unit
  • O = Organization
  • L = Locality
  • ST = State
  • C = Country
  • DC = Domain Component