IP Addressing

IP Address

A unique number given to a network-connected device that serves as its identifier.

Public IP

Public, unique IP address assigned to a modem by the ISP.

Modem

Allows a network to communicate with an ISP.

Private IP

Internal-only IP addresses that are not publicly registered on the internet.

Network Address Translation (NAT)

Translates private IP addresses to public & vice versa.

Port Address Translation (PAT)

Allows multiple devices to share a single public IP address by using port numbers. Each port number points to an internal IP.

Class A

Used in large networks

Range: 10.0.0.0 - 10.255.255.255
Default Subnet Mask: 255.0.0.0

Class B

Used in medium-sized networks

Range: 172.16.0.0 - 172.31.255.255
Default Subnet Mask: 255.240.0.0

Class C

Used in smaller networks

Range: 192.168.0.0 - 192.168.255.255
Default Subnet Mask: 255.255.0.0

IPv4 Address

32-bit numerical identifier composed of 4 octets separated by decimals.

Network ID

The portion of an IP address that shows which network a device belongs to.

Host ID

The portion of an IP address that identifies a specific device on a network.

Subnet Mask

Reveals how many bits in an IP address are used for the network ID.

Subnetting

Dividing a large network into smaller networks using IP addresses.

CIDR Notation

Represents a subnet mask by the network bit count preceded by a forward slash.

Host Bit

Denoted by a “0” in the binary version of a subnet mask.

Network Bit

Denoted by a “1” in the binary version of a subnet mask.

Octet

A group of 8 bits.

IPv6 Address

128-bit alphanumerical identifier composed of 8 hextets separated by decimals.

Compression

A method used to shorten IPv6 addresses into a compact, readable format.

Compression Rules

1. If there are 0s leading a hextet, they can be omitted, the last digit must remain even if it is also a 0.

2. If there are two or more consecutive hextets composed of all 0s, they can be represented with a double colon (::)/

Tunneling

When IPv6 packets are enclosed within IPv4 packets so routing can be achieved between the versions.

Dual Stack

Allows IPv4 and IPv6 data to be processed simultaneously.

NAT64

Inserts an IPv4 address inside an IPv6 prefix so IPv6-only devices can communicate with IPv4-only servers.

Prefix

Portion of an IPv6 address that shows which network a device belongs to.