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Developer Tools2026-03-195 min read

IP Subnet Cheat Sheet: CIDR, Masks & Ranges

Quick reference for IP subnetting: CIDR notation, subnet masks, host counts, and common subnet sizes.

CIDR Quick Reference

/32  255.255.255.255  1 host\n/31  255.255.255.254  2 hosts (point-to-point)\n/30  255.255.255.252  4 hosts (2 usable)\n/28  255.255.255.240  16 hosts\n/24  255.255.255.0    256 hosts (254 usable)\n/20  255.255.240.0    4,096 hosts\n/16  255.255.0.0      65,536 hosts\n/8   255.0.0.0        16.7M hosts

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