Detect overlapping address space across lists or tenants.
Compare two lists to avoid routing conflicts.
This page checks two lists of CIDR blocks for overlap without changing the existing form, report selector, or result card layout. It is designed for situations where a simple two subnet comparison is not enough and you need to validate larger planned or inherited address lists.
Paste one CIDR per line into list A and list B. The report mode changes how much detail you want to see, while the owner field helps label the comparison in operational workflows.
Each CIDR is converted into a numeric start and end boundary, then every relevant range is compared for containment or intersection. The result is technical overlap analysis, not a business judgment about whether the conflict matters in your environment.
If list A contains 10.0.0.0/24 and list B contains 10.0.0.0/25, the result should report containment because the smaller prefix fits inside the larger one. If list B instead contains 10.0.1.0/24, the result should show no overlap.
Use this page for tenant isolation reviews, mergers, VPN integration, cloud migration planning, and cleaning up address spreadsheets that were assembled by multiple teams.
The output is strictly mathematical overlap analysis. It does not know whether NAT, VRFs, or policy isolation make a collision acceptable in practice. Use the result as evidence, then apply your environment rules separately.
It compares two lists of CIDR blocks and shows whether any entries overlap, contain one another, or create address conflicts.
It helps when you need to compare many planned or inherited prefixes at once instead of checking subnets one pair at a time.
Yes. One block can partially overlap another or sit fully inside a larger prefix, and both cases can matter operationally.
It is useful for multi tenant planning, mergers, cloud migrations, route validation, and cleaning up undocumented address lists.
No. It reports the technical overlap. Whether the overlap is acceptable depends on isolation, NAT, VRFs, and your operational policy.
The output is based on the CIDR lists you enter. It does not know ownership, routing policy, or network segmentation outside those inputs.
Check one IPv4 pair at a time with more focused detail.
Review overlap relationships for IPv6 prefixes.
Convert raw address spans into prefixes before list based comparison.