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Version: 2.2.1-preview

AD-SUB-10 - Distinct first three octets (/24 networks) count should be retrievable

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

Overview​

Analyzing /24 network distribution provides:

  • Subnet granularity: Understanding the typical subnet size in use
  • Location mapping: Each /24 often represents a specific location or VLAN
  • Capacity insight: How many discrete network segments exist
  • Documentation: Detailed network topology information

/24 networks (254 hosts) are the most common subnet size for client networks.

Security Recommendation​

  • Document the purpose of each /24 network
  • Align /24 boundaries with physical locations or security zones
  • Plan /24 allocation to support VLAN and location requirements
  • Review /24 utilization for optimization opportunities

How the Test Works​

This test extracts the first three octets from all IPv4 subnets and counts the distinct /24 networks.

  • Test-MtAdSubnetFirstOctetCount - Analyzes first octets
  • Test-MtAdSubnetFirstTwoOctetsCount - Analyzes /16 networks
  • Test-MtAdSubnetTotalCount - Counts total subnets

Test Metadata​

FieldValue
Test IDAD-SUB-10
SeverityInfo
SuiteActive Directory
CategoryAD.Site
PowerShell testTest-MtAdSubnetFirstThreeOctetsCount
TagsAD, AD-SUB-10, AD.Site

Source​

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