Paste a list of IPv4 CIDR blocks, single IPs, or a.b.c.d-e.f.g.h ranges. The tool merges overlapping or adjacent prefixes into the smallest equivalent set of CIDR blocks — useful for firewall rules, route tables, and ACL minimization.
Each input is converted to a numeric [start, end] interval. Intervals are sorted and merged when they touch or overlap. Each merged interval is then split into the largest CIDR blocks that fit at aligned boundaries — the same algorithm used by aggregate6, netaddr.cidr_merge, and Cisco's route summarization.
Lines starting with # are treated as comments. Whitespace and empty lines are ignored. Single IPs become /32 blocks.