Dev / Networking
IPv4 Subnets.
CIDR notation packs an IP address and a prefix length into one string. This calculator shows the network address, broadcast, usable host range, and dotted-decimal netmask.
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Reading CIDR
A /24 means the first 24 bits are the network portion — 256 addresses, 254 usable hosts. Smaller prefixes (/16, /8) mean bigger networks. Private ranges (10.x, 172.16–31.x, 192.168.x) are defined in RFC 1918.