JA Technology Solutions
CIDR Range & Overlap Tool
Detect overlaps between CIDR blocks, merge adjacent ranges, and check IP containment.
CIDR Range & Overlap Tool
Paste a list of IPv4 CIDR blocks to detect overlaps, merge adjacent ranges into the smallest supernet covering them (CIDR aggregation), and check whether a specific IP address is contained in any of the ranges. Designed for firewall rule cleanup, ACL audits, and route table analysis.
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Why CIDR Math Matters
Firewall rules, route tables, and ACLs accumulate over years. New rules get added when networks expand, but old rules rarely get cleaned up. The result is overlapping ranges, redundant entries, and rules that contradict each other. Detecting overlap and merging adjacent CIDR blocks reduces rule count, improves lookup performance, and makes audits feasible.
CIDR Aggregation
Two adjacent /25 blocks that share the same parent /24 can be merged into a single /24 entry — the same number of addresses, half the rules. Multi-level aggregation can compress dozens of entries into a handful. This tool performs that aggregation automatically and shows which input ranges contributed to each merged supernet.
Where CIDR Work Shows Up in My Projects
CIDR cleanup, aggregation, and overlap detection most often come up as part of the integration, custom development, and custom reporting work I take on — building API-driven automation against enterprise network and security platforms, consolidating firewall and route-table inventory data, or producing operational reports that flag rule drift over time. Learn about integration services or get in touch to discuss a project where network data and application work overlap.
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