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Active Directory

From Active Directory for Dummies

Physical vs logical parts of AD

  • Physical part = domain controllers AD runs on
  • Logical part = modelling your org with AD

Services in the AD Umbrella

  1. AD Domain Services (ADDS)
  2. AD LDAP - ADDS with fewer features
  3. AD Federation Services - SSO service
  4. AD Certificate Services - create CAs, renew/revoke public key certs
  5. AD Rights Management Services - create policies like user can't email doc to unauthorized ppl

Components of AD


  • has at least 1 domain controller
  • directory database - replicated btwn all DCs
  • can create child domains to form a tree of domains


  • a forest is a group of trees that share the same schema and global catalog

OUs and Objects

  • OUs = "folders". for example - "west", "east"
  • Objects - have an object class and attributes


  • lists object classes available
  • for each object class, you must specify name, Object Identifier, required attributes, optional attributes
  • AD installed with a base schema by default

Global Catalog

  • indexes all the objects in a forest so they're searchable
  • but only indexes attributes you specify in the schema

AD Tree or Forest?

  • use a forest if you need to use more than 1 namespace
  • one namespace: = 1 domain
One Domain: - 1 OU - 1 OU
  • multiple namespaces -, = domains grouped in 1 forest
One Forest: - 1 OU - 1 OU

Domains in the same forest share

  • the same schema
  • the same configuration partition (?)
  • 2-way Kerberos trust
  • a common "Enterprise Administrators" group
  • only group allowed to make forest-wide changes, like adding/removing a domain
  • same global catalog

Organizing with OUs

  • each OU is in exactly 1 domain
  • an OU can't contain objects from other domains

Patterns for organizing a domain's objects into OUs

  • object-based. domain has OUs for users, printers, computers. most flexible
  • administrative
  • division/department
  • can assign an administrator to an OU

Stable Domains and Transient OUs

  • domains should be stable - objects should not move frequently btwn domains
  • base domains on geography, not department/function/etc
  • OUs are for transient groupings, like project

Example: [root domain]

- [domain]
  - [ou]
  - [ou]
  - [ou]
- [domain]
- [domain]
  • here, you have a tree of domains

  • now, if Flexport buys (but keeps it independent), then it'll have 2 trees - and

  • Flexport can then combine and into a forest - so 1 central group can administer both, the trees share a schema, etc

Physical AD layout

  • can replicate your domain controllers (DCs)
  • can select domain controllers to store global catalogs
  • guideline - have a DC at each branch office with >= 50 people to speed up authentication requests
  • have a DC at any office with applications running which require AD authentication

Managing users and groups

Creating user objects

Open AD Users and Groups (ADUC) application from Server Manager in Windows Server

LDIFDE = import objects from LDIF file CSVDE = import objects from CSV file

Types of groups

  • Domain local groups = only valid within their local domain
  • Global groups = valid within specified domains
  • Universal groups = valid across all domains in a forest

Uses of groups

  • Security - to restrict access to specific people. Can give 1 group read-only access, another write access too, etc
  • Distribution - say you wanted to email all employees in California