IP Addressing & Subnets

IP Addressing

Concept	Detail
IPv4	32-bit, e.g. `192.168.1.10`
IPv6	128-bit, e.g. `2001:db8::1`
CIDR	`/24` = 255.255.255.0 = 256 addresses
Private ranges	`10.0.0.0/8`, `172.16.0.0/12`, `192.168.0.0/16`
Loopback	`127.0.0.1` (`localhost`)

Common CIDR sizes: /24 → 254 usable hosts, /16 → 65,534, /30 → 2 (point-to-point links).

Exam tip: The network address (all host bits 0) and broadcast address (all host bits 1) are not assignable to hosts - that's why /24 gives 254, not 256, usable addresses.