IP Addressing

IPv4 Foundations

An IPv4 address is a 32-bit logical identifier written as four decimal octets. A prefix length marks the network bits; the remaining bits identify hosts.

One binary digit

Bit

A bit is 0 or 1. Eight bits form one octet with a decimal range of 0 through 255.

All host bits 0

Network address

Identifies the subnet for routing and is not assigned to an ordinary host.

All host bits 1

Broadcast address

Reaches every IPv4 host in the subnet. Assignable host addresses fall between network and broadcast.

Leading network bits

Prefix length

Written /n; defines the boundary between network bits and host bits.

Core structureIPv4 is hierarchical: network bits identify the subnet; host bits identify an interface inside that subnet.

Binary Octet Converter

Enter a decimal octet from 0 to 255 to see its eight binary place values.

Example10101100 = 128 + 32 + 8 + 4 = 172.

Historical Address Classes

Class	First octet	Default prefix	Use
A	1–126	/8	Very large host networks
B	128–191	/16	Medium networks
C	192–223	/24	Smaller networks
D	224–239	None	Multicast
E	240–255	None	Experimental / reserved

High priorityClassful ranges remain exam knowledge, but modern networks use CIDR prefix length—not the first octet—to determine the real network boundary.

Network, Host & Broadcast

Example network	First usable	Last usable	Broadcast
10.0.0.0/8	10.0.0.1	10.255.255.254	10.255.255.255
172.16.0.0/16	172.16.0.1	172.16.255.254	172.16.255.255
192.168.100.0/24	192.168.100.1	192.168.100.254	192.168.100.255

Host-bit ruleAll host bits 0 = network. All host bits 1 = broadcast. Assignable hosts fall between them.

IPv4 Address Classifier

Select an address to reveal its range and practical meaning.

Public, Private & APIPA

RFC 1918

10.0.0.0/8

Private range 10.0.0.0 through 10.255.255.255.

RFC 1918

172.16.0.0/12

Private only from 172.16.0.0 through 172.31.255.255—not every 172 address.

RFC 1918

192.168.0.0/16

Private range 192.168.0.0 through 192.168.255.255.

DHCP failure clue

169.254.0.0/16

APIPA provides local-link communication but no usable default gateway automatically.

Security notePrivate does not automatically mean secure. Filtering, authentication, segmentation, and patching are still required.

CIDR, VLSM & Delivery

Delivery	Pattern	Key behavior
Unicast	One to one	Packet targets one interface
Broadcast	One to all	All hosts in the IPv4 broadcast domain
Multicast	One to subscribed group	Uses 224.0.0.0/4

IPv6 differenceIPv6 eliminates broadcast and uses multicast and anycast for discovery and service functions.

IPv6 Foundations & Notation

IPv6 uses 128 bits written as eight 16-bit hexadecimal blocks. It expands address capacity and makes autoconfiguration, multicast, anycast, and neighbour discovery central features.

Public Internet

Global unicast

2000::/3 is globally routable IPv6 space.

Same link only

Link-local

FE80::/10 supports neighbour discovery and is never routed beyond the link.

Internal routing

Unique local

FC00::/7 is routable inside an organization but not on the public Internet.

One to group

Multicast

FF00::/8 replaces many functions that used IPv4 broadcast.

IPv6 Compression Explorer

Remove leading zeros in each block, then replace one contiguous run of zero blocks with ::. The double colon may appear only once.

Double-colon rule:: can replace one run of consecutive zero blocks only once per address.

IPv6 Address-Type Explorer

No IPv6 broadcastIPv6 supports unicast, multicast, and anycast—but has no broadcast address type.

SLAAC Sequence Builder

SLAAC creates IPv6 addressing without a stateful address server.

Host starts IPv6 initialization.

Modified EUI-64

Modified EUI-64 derives a 64-bit interface ID from a 48-bit MAC address.

1 · SPLITTwo 24-bit halves

→

2 · INSERTFF:FE in the middle

→

3 · FLIPInvert the U/L bit

→

4 · APPENDAdd to /64 prefix

Privacy noteModern systems often prefer randomized or stable privacy identifiers, but EUI-64 remains important exam knowledge.

SLAAC, DHCPv6 & Transition

Stateless address

SLAAC

Host builds its address from a router-advertised prefix; no lease database is required.

Extra settings

Stateless DHCPv6

SLAAC builds the address while DHCPv6 supplies options such as DNS.

Tracked lease

Stateful DHCPv6

A server assigns and tracks the IPv6 address and supplies options.

Coexistence

Dual stack

Runs IPv4 and IPv6 simultaneously; flexible but both must be operated and secured.

Carry inside

Tunneling

Encapsulates IPv6 across an IPv4-only section, adding overhead and possible NAT complications.

Translate

NAT64

Translates between IPv6-only clients and IPv4-only services, often with DNS64.

Migration ruleDual stack provides both protocols. Tunneling carries one inside another. NAT64 translates between them.

PowerShell 7 Practice

Get-NetIPAddressAddresses, prefixes, families, origins

Get-NetIPAddress -AddressFamily IPv4IPv4 only

Get-NetIPAddress -AddressFamily IPv6IPv6 only

Get-NetRoute -AddressFamily IPv4IPv4 routes and default route

Get-NetNeighborARP and IPv6 neighbours

Test-NetConnection 127.0.0.1IPv4 loopback

Test-NetConnection ::1IPv6 loopback

Resolve-DnsName example.com -Type AAAAIPv6 DNS record

Exam Check

Fifteen review questions drawn directly from the Chapter 7 manual.

Score: 0 / 0