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Directory Servers Overview

Jun 19, 2025

Overview

This lecture introduces directory servers, their structure, benefits, and the roles of systems administrators in their setup and management.

Directory Servers & Their Purpose

  • A directory server provides a lookup service to map network resources to their network addresses.
  • Directory servers store information about user accounts, user groups, telephone numbers, and network shares centrally.
  • Centralizing information on a directory server simplifies access and management compared to local storage on each machine.

Replication & Redundancy

  • Replication allows directory data to be copied across multiple servers, presenting a unified data store.
  • Replication provides redundancy, minimizing service disruption if one server fails.
  • Replication reduces query latency by placing directory replicas close to users in multiple locations.

Hierarchical Structure & Organizational Units (OUs)

  • Directory servers use a hierarchical model with containers called organizational units (OUs).
  • OUs can contain objects (like user accounts) or additional sub-OUs, similar to folders and subfolders in a file system.
  • Hierarchical organization aids in data management and reflects organizational structure (e.g., by department).
  • Changes to a parent OU apply to its sub-OUs; for example, stricter password policies for a department.

Directory Service Flexibility & Accessibility

  • Directory service should allow creation of new object types as organizational needs evolve.
  • Information stored in directory servers should be accessible from different operating systems and network locations.

Systems Administrator Responsibilities

  • System admins are responsible for installing, configuring, and maintaining the directory server and its operating system.
  • Admin duties include updating the OS, installing the directory service, configuring replication, and designing the directory hierarchy.

Key Terms & Definitions

  • Directory Server — A server that provides a lookup service for mapping resources to network addresses.
  • Replication — The process of copying data across multiple servers for redundancy and improved access speed.
  • Organizational Unit (OU) — A container within a directory server for organizing objects, similar to a folder.
  • Object — An individual item in a directory, such as a user account or a group.

Action Items / Next Steps

  • Review key directory service concepts and the structure of organizational units.
  • Consider how directory servers can be designed for redundancy and efficient management.