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Version: 2.2.1-preview

AD-SUB-06 - Non-RFC1918 (public IP) subnets count should be retrievable

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

Overview​

Using public IP addresses internally can cause:

  • Routing conflicts: If public IPs are also used on the internet
  • Security risks: Internal resources may be exposed
  • Compliance issues: Violation of IP address allocation standards
  • Connectivity problems: NAT and firewall complications

RFC1918 private ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) should be used for internal networks.

Security Recommendation​

  • Use RFC1918 private IP ranges for internal networks
  • If public IPs are required internally, ensure proper isolation
  • Document any exceptions with business justification
  • Review subnet assignments for compliance

How the Test Works​

This test identifies subnets that use public IP address ranges outside of RFC1918 private ranges.

  • Test-MtAdSubnetNonInternalDetails - Lists public IP subnets
  • Test-MtAdSubnetTotalCount - Counts total subnets
  • Test-MtAdSubnetCatchAllCount - Identifies overly broad subnets

Test Metadata​

FieldValue
Test IDAD-SUB-06
SeverityInfo
SuiteActive Directory
CategoryAD.Site
PowerShell testTest-MtAdSubnetNonInternalCount
TagsAD, AD-SUB-06, AD.Site

Source​

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