LDAP aware applications:

LDAP API are available for a number of programming languages, including C, Java, and Perl.

Application example:

Apache web server E-mail clients: Netscape, Mozilla, Outlook, Sendmail, Samba

LDAP for user Authentication:

Services example

login, rlogin, rsh, rexec, ftp, passwd, su, sudo, ssh, imap, pop3, xdm...
To work with LDAP, PAM modules should be configured for accessing LDAP.
/etc/nsswitch.conf may also need to be configured to point at LDAP for the generic Unix PAM module.

References:

OpenLDAP Everywhere by Craig Swanson and Matt Lung in Linux Journal
OpenLDAP Administrator's Guide
LDAP for Rocket Scientists

Unix Authentication and Naming services
What is LDAP
LDAP heirarchy
Addressing in LDAP
Data tree with dn
Schema
Accessing LDAP
OpenLDAP installation steps
Server Config file
Exercises: Server installation
Exercises: Client installation
Outline of LDIF
LDIF example
Frequent LDAP commands
Exercises: LDAP commands
Performance
Access Control List
LDAP over SSL/TLS
LDAP Applications
Exercises: LDAP user authentication
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