AD & O365 Divestiture Segmentation

🔀 AD & O365 Divestiture Segmentation

Objectives:

  • Perform complete discovery of AD and Microsoft 365 assets.

  • Identify all users, computers, and services to be retained or transitioned.

  • Map and document GPOs, DNS zones, file shares, and integrated services.

  • Prepare the environment for safe migration and organizational separation.

  • Provide clean data sets for auditors, engineers, and decision-makers.
  1. Discovery & Inventory Collection:
    • Developed PowerShell scripts to gather information about:
      • User and group accounts with OU paths and membership trees
      • Computer accounts with OS version, last login, and descriptions
      • Group Policy Objects (GPOs) with linked OUs and WMI filters
      • AD-integrated DNS zones and host records
      • File shares, DFS links, and access control lists (ACLs)
    • Cross-referenced objects with HR and asset ownership records

  2. Classification & Ownership Mapping:
    • Exported CSVs categorizing:
      • Stay-behind vs. migrating assets
      • Shared vs. exclusive resources
    • Identified OUs for realignment or creation
    • Validated mappings with stakeholders
    • Documented results for internal and external audit

  3. GPO & Infrastructure Analysis:
    • Audited GPOs for:
      • Login scripts, drive mappings, and software deployment
      • Firewall rules, credential policies, and inheritance scopes
    • Flagged cross-tenant GPOs for removal or replacement
    • Identified shared network infrastructure and login dependencies

  4. DNS & Service Segmentation:
    • Mapped internal DNS zones to services (e.g., file servers, printers, domain controllers)
    • Flagged zones for migration or split-horizon reconfiguration
    • Documented DNS entries tied to third-party/shared systems

  5. Microsoft 365 / Azure AD Audit:
    • Exported users, license usage, mailbox data, and domain federation details
    • Identified:
      • Shared mailboxes, distribution groups, Teams memberships
      • Cloud-native vs. synchronized accounts
      • Federated domain dependencies
    • Created ownership lists and transfer paths for M365 objects

  6. Validation & Pre-Migration Planning:
    • Performed dry-run tests of OU realignment and GPO scoping
    • Validated access after removal of test resources
    • Prepared migration playbooks for the transition team

Result:

This project provided the technical foundation for a clean IT divestiture, ensuring:
  • Clear and documented ownership of AD and M365 resources
  • Reduced post-split disruption through proactive mapping
  • Secured segmentation of systems