# FSMO role holder details should be retrievable

Understanding FSMO (Flexible Single Master Operations) role distribution is critical for:

Source: https://maester.dev/docs/tests/AD-DC-06

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<div class="test-byline"><div class="test-byline-avatars"><a class="test-byline-avatar test-byline-avatar--author" href="/contributors/soulemike" title="Michael Soule · Original author"><img src="https://github.com/soulemike.png" alt="Michael Soule" width="28" height="28" loading="lazy" decoding="async" /></a></div><div class="test-byline-meta"><span class="test-byline-text">Contributed by <a href="/contributors/soulemike">Michael Soule</a></span><a class="test-byline-link" href="/contributors">All contributors →</a></div></div>

<p class="test-part">Part of <a href="/docs/tests/ad">Active Directory</a> · Active Directory · Domain controllers · <a href="/docs/tests">All checks</a></p>

```powershell title="Run this check"
Invoke-Maester -TestId AD-DC-06
```

## Overview

Understanding FSMO (Flexible Single Master Operations) role distribution is critical for:

- **Operational awareness**: Knowing which DCs perform critical directory operations
- **Disaster recovery**: Being able to quickly seize roles if a DC fails
- **Maintenance planning**: Understanding impact of DC downtime
- **Security monitoring**: Tracking changes to FSMO role holders

The 5 FSMO roles are:
1. **Schema Master** (forest-wide): Controls Active Directory schema updates
2. **Domain Naming Master** (forest-wide): Controls domain additions and removals
3. **PDC Emulator** (domain-wide): Primary DC for backward compatibility and time sync
4. **RID Master** (domain-wide): Allocates relative IDs for security identifiers
5. **Infrastructure Master** (domain-wide): Handles cross-domain object references

#### Control Type

**Operational**

#### Security Recommendation

- Document your FSMO role holders and keep the documentation updated
- Ensure FSMO role holders are highly available DCs
- Place at least one role holder in a different site for geographic redundancy
- Monitor for unexpected FSMO role transfers
- Test FSMO role seizure procedures periodically

#### How the Test Works

This test retrieves the current FSMO role holders from the domain and forest objects, then displays:
- Which DC holds each FSMO role
- How many roles each DC holds
- Total number of unique FSMO role holders

#### Related Tests

- `Test-MtAdDcAllFsmoRolesCount` - Identifies DCs holding all 5 roles
- `Test-MtAdDomainControllerCount` - Total DC count

## Details

<details>
<summary>Every attribute of this check</summary>

| Field | Value |
| --- | --- |
| Test ID | AD-DC-06 |
| Severity | Info |
| Suite | Active Directory |
| Product | Active Directory |
| Feature | Domain controllers |
| Area | Infrastructure hardening |
| Resource type | DomainController |
| MITRE ATT&CK | None |
| PowerShell test | [Test-MtAdDcFsmoRoleHolderDetails](https://github.com/maester365/maester/blob/main/tests/ad/domain-controller/Test.AD-DC-06.ps1) |
| Services | ActiveDirectory |
| Permissions | ActiveDirectory:Ldap:domainDNS:ReadProperty, ActiveDirectory:Ldap:nTDSDSA:ReadProperty, ActiveDirectory:Ldap:crossRef:ReadProperty |

</details>

## Source

- Test: [`tests/ad/domain-controller/Test.AD-DC-06.ps1`](https://github.com/maester365/maester/blob/main/tests/ad/domain-controller/Test.AD-DC-06.ps1)
- Documentation: [`tests/ad/domain-controller/Test.AD-DC-06.md`](https://github.com/maester365/maester/blob/main/tests/ad/domain-controller/Test.AD-DC-06.md)