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Version: 2.2.1-preview

AD-SUB-08 - Distinct first octets count should be retrievable

Michael SouleMerill Fernando
Contributed by Michael Soule with Merill FernandoAll contributors →

Overview​

Analyzing subnet distribution by first octet provides:

  • Addressing scheme visibility: Understanding IP allocation patterns
  • Network segmentation insight: How the network is logically divided
  • Capacity planning: Identifying available address space
  • Documentation: Supporting network topology documentation

Common patterns include using 10.x for corporate, 172.x for datacenters, etc.

Security Recommendation​

  • Document the IP addressing scheme and first octet allocation
  • Plan address space to avoid conflicts during acquisitions
  • Reserve address space for future growth
  • Review addressing scheme during network architecture changes

How the Test Works​

This test extracts the first octet from all IPv4 subnets and counts the distinct values.

  • Test-MtAdSubnetFirstTwoOctetsCount - Analyzes /16 networks
  • Test-MtAdSubnetFirstThreeOctetsCount - Analyzes /24 networks
  • Test-MtAdSubnetTotalCount - Counts total subnets

Test Metadata​

FieldValue
Test IDAD-SUB-08
SeverityInfo
SuiteActive Directory
CategoryAD.Site
PowerShell testTest-MtAdSubnetFirstOctetCount
TagsAD, AD-SUB-08, AD.Site

Source​

  • Pester test: tests/ad/site/Test-MtAdSubnetFirstOctetCount.Tests.ps1
  • PowerShell source: powershell/public/ad/site/Test-MtAdSubnetFirstOctetCount.ps1