Linux HowTo: LDAP Basics

LDAP or Lightweight Directory Access Protocol
        - a set of open protocols developed at University of Michigan in 1992
        - it is a simple database of information on a network (not rdbms); microsoft active directory uses ldap concept.
        - data is organized in a hierarchial client server structure (like dns) - called 'directory info tree'   

-how ldap works?
        - client connects to ldap server    - this is called binding
        - server authenticates
        - client queries the server

-ldap can store a variety of data - like plain text, binary, images or public key certificates etc.
-it can serve as a authentication or id management system;       it can completely replace nis.
-it can serve as dns, mail router etc.

-ldap terms:
        . entry        -    unit of ldap data                -like primary key
        . attribute    -    addtional support data for entry        -like columns depending on primary key
        . objectclass    -    special attributes                -like composite primary keys
        . schema    -    a set of ldap rules                -like data dictionary
        . ldif        -    plaintext 'ldap data interchange format    -like sql output or sqlldr

-ldap daemons:
        . slapd    -    standalone ldap daemon        - like a listener
        . slurpd    -    standalone replication daemon    - like db link for data exchange bet servers
    -note:      openldap    -    is opensource implementation of ldap

-To install openldap server and clients in one go:
        # yum    -y install    openldap-servers    openldap-clients               [ multiple pkgs in one cmd ]
-To configure openldap server , edit the following file:
        # vim    /etc/openldap/slapd.conf
-To start / stop openldap server:
        # service  ldap    start | stop | status
-To query ldap server, the foll cmd is used:
        # ldapsearch    <options>
-To configure ldap client:
        # system-config-authentication