Directory Services BICS 565

What is a Directory Service (DS)? A service that allows users to lookup information about entities in an organization Entities can be people, computers, a collection of computers, peripherals, and non-traditional computing devices Entities are generally termed as “objects”, that exist in a hierarchy of the organization.

Why a DS? A directory allows fast “lookup” services A directory allows quick authentication of basic information such as addresses, passwords, URLs. Directory service “points” to other entities, but does not necessarily store them. –For example, a phone book has a phone number of a person, but does not contain his or her website.

Why not a DB? Why not use a database instead of a directory service? –Overkill –DS is good for fast lookups: infrequent writes, frequent reads.

Why not a DB? Databases can perform complex searches, and generate reports However, a DS is well suited for the job of a “pointer” service to other entities. A DB can work as a DS, but is not really suited for the job.

DS + Network A DS is one of the most closely integrated concepts to a network Host information on users, their groups, their organizational units (for example, accounting, marketing, etc.)

DS + Network Host information on computers in a network, DHCP, DNS and other network information. Physical and Data Link layer information for all computers on a network Inventory of software, drivers and updates along with user privileges for its use. A DS to store a DS.(???)

X.500 An OSI standard. Directory Access Protocol to access heavyweight directories Lightweight Directory Access Protocol (LDAP) was created as a client to X.500 LDAP can itself be a DS

LDAP Keywords “Lightweight” and “Directory” Lightweight is used to indicate the use of TCP/IP for all access. No other suite is supported. Originally designed as a directory “access” protocol, it grew and became popular as a directory service itself.

LDAP First developed at the Univ. of Michigan, then adapted to several environments such as Netscape Directory Service, and Active Directory –Netscape DS –Solaris –Novell –Active Directory

Hierarchy All LDAP applications use a hierarchy structure to address the relationship between different objects in the DS. Tree structure embeds objects inside an organizational unit (OU) that is part of an organization (O).

LDAP as a base LDAP specifications as per the RFC 1777 and RFC 2251 is being developed further by independent groups. OpenLDAP is an opensource effort to accelerate LDAP as an open standard. Netscape has embedded the same LDAP in its directory service.

Other Directory Projects Active Directory Netscape Directory

Directory Services Emphasis on “service” Distributed Approach Embedded Knowledge