AD-SUB-05: IPv6 catch-all subnets count should be retrievable
| ID | AD-SUB-05 |
| Severity | Info |
| Suite | Active Directory (on-premises) |
| Product | Active Directory |
| Feature | Sites and subnets |
| Security area | Infrastructure hardening |
| Resource type | AdSite |
| Reads from | On-premises Active Directory |
What this checks and how to fix it
Section titled “What this checks and how to fix it”Overly broad IPv6 subnets can cause similar issues to IPv4 catch-all subnets:
- Authentication inefficiency: Clients may authenticate to distant DCs
- Suboptimal routing: Site boundaries don’t reflect actual topology
- Management complexity: Difficult to track client locations
- Security concerns: Reduced granularity in access controls
IPv6 /48 prefixes or larger are considered catch-all ranges.
Control Type
Section titled “Control Type”Operational
Security Recommendation
Section titled “Security Recommendation”- Use appropriately-sized IPv6 subnets (typically /64 for client networks)
- Align IPv6 subnet boundaries with physical locations
- Document IPv6 subnet allocation scheme
- Review IPv6 subnet definitions regularly
How the Test Works
Section titled “How the Test Works”This test identifies IPv6 subnets with overly broad prefixes (/48 or smaller).
Related Tests
Section titled “Related Tests”Test-MtAdSubnetIpv6Count- Counts IPv6 subnetsTest-MtAdSubnetCatchAllCount- Identifies IPv4 catch-all subnetsTest-MtAdSubnetTotalCount- Counts total subnets
Mito check. Author: soulemike. Open-source licences.
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