CIDRGen Guides & Examples
Practical, no-fluff documentation for CIDRGen — written by people who hit the problems first.
About CIDRGen
What cidrgen computes for IPv4 and IPv6 prefixes, how it reports blocks whose host bits are set, and the three companion tools for splitting, overlap checking and mask conversion.
CIDRGen Changelog
Dated changes to cidrgen: the move to the shared site template, the calculator now computing the ranges its description promised, and the new splitter, overlap checker and mask converter.
CIDR Cheat Sheet: Every IPv4 Prefix, /0 to /32
Netmask, wildcard, total and usable addresses for every IPv4 prefix length, the /31 and /32 exceptions, the IPv6 prefixes that matter, and the private ranges.
CIDR Overlaps and Aggregation: Finding Conflicts Before a Route Does
How blocks overlap (identical, contained, partial), why CIDR blocks can only nest or be disjoint, how aggregation merges adjacent blocks, and what the overlap checker reports.
Subnetting Without Math: The Block-Size Trick
Find the network, broadcast and usable range of any IPv4 address by looking at one octet, size a subnet for N hosts, and the cloud reservations that change the answer.
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