IPv4 Addressing and Subnetting Review

Vocabulary flashcards covering binary conversions, IPv4 addressing basics, address classes, private ranges, subnetting terminology, and routing concepts.

IPv4

Stands for Internet Protocol version 4; a $32$-bit address composed of $4$ octets.

Octet

A grouping of $8$ bits; an IPv4 address contains four of these.

Dotted decimal notation

The numbering format normally used to write an IPv4 address.

Network portion

The part of the IP address that identifies which network the device belongs to.

Host portion

The part of the IP address that identifies a specific device on the network.

Subnet mask

The value that determines where the line falls between the network portion and host portion of an address.

CIDR

Classless Inter-Domain Routing.

Prefix length

Also known as slash notation (e.g., $/24$), it represents the number of bits used for the network portion of the address.

Private IP address range (Class A)

$10.0.0.0$ to $10.255.255.255$.

Private IP address range (Class B)

$172.16.0.0$ to $172.31.255.255$.

Private IP address range (Class C)

$192.168.0.0$ to $192.168.255.255$.

Public IP address

An IP address that is globally unique and routable on the internet.

NAT

Network Address Translation; the technology that allows devices with private IPs to reach the internet.

IPv4 loopback address

$127.0.0.1$; commonly used for local testing.

Subnetting

The process of dividing one larger network into smaller, more efficient sub-networks by borrowing host bits.

Block size (magic number)

Calculated as $256$ minus the subnet mask value in the interesting octet.

Network address

An IP address where all host bits are set to zero, identifying the specific subnet.

Broadcast address

The address where all host bits within a subnet are set to $1$, used to communicate with all hosts on that subnet.

APIPA

Automatic Private IP Addressing ($169.254.0.0/16$); assigned when a DHCP server is unreachable.

IPv4 multicast traffic range

$224.0.0.0/4$ (Class D addresses).

Route summarization

Also called supernetting or aggregation; combining multiple contiguous networks into a single, larger advertised route.

VLSM

Variable Length Subnet Masking; using different prefix lengths for different subnets based on actual host requirements.

FLSM

Fixed Length Subnet Masking; applying the same subnet mask to every subnet in the network.

Wildcard mask

The inverse of a subnet mask (calculated by subtracting each octet from $255$) used in ACLs or OSPF statements.

VLANs

Virtual LANs; a concept used to isolate systems into separate broadcast domains on shared switches.