IP v4, IPv6 & MAC Addresses
Introduction to IPv4
Example: 192.168.0.1
Internet Protocol Version 4 is the underlying technology that allows devices to communicate with each other over the internet and other IP-based networks. It was originally designed in the early 1980s and has been widely used since the early days of the internet.
The purpose of IPv4 is route data to it's final address through the internet.
IP Addresses are logical addresses that reflect their logical location within the network they are connected to and are used by routers to route traffic between networks.
IPv4 Address Structure
192.168.0.1
IPv4 addresses are 32 bits in length, which allows for a total of approximately 4.3 billion unique addresses. Each IPv4 address is typically represented as four decimal numbers separated by periods.
- Split into four parts ( 8 bits per subaddress)
- Separated by periods (full stops)
- Written in denary
- Each sub address has values of 0 - 255
Public IP Addresses
Public IP addresses are unique identifiers that are used for communication between devices on the internet and are crucial for identifying and routing data to specific devices or servers worldwide.
Internet Service Providers (ISPs) allocate public IP addresses to their customers, allowing them to access websites, online services, and resources on the internet.
Public IP addresses can be either static (unchanging) or dynamic (changing periodically) depending on the type of internet connection.
Examples: 8.8.8.8, 142.250.0.0
Characteristics:
- Globally unique.
- Can be accessed directly from anywhere on the Internet (unless blocked by firewalls).
Private IP Addresses
Private IP addresses are used to identify devices within local or private networks, such as home networks, business intranets, or corporate LANs. Unlike public IP addresses, private IP addresses are not globally routable and cannot be used to directly access devices on the internet.
Private IP addresses provide a level of security by keeping internal network devices hidden from direct exposure to the internet, which can help protect against external threats and unauthorized access.
In order for data to be routed across the internet from a private IP address, the address must be replaced with a public IP address, using Network Address Translation (NAT).
Characteristics:
- Not unique globally; the same private address can exist in multiple networks.
- Requires NAT (Network Address Translation) to communicate with the Internet.
IP Address Exhaustion
The limited number of IP addresses available (4.3 billion in total) means that eventually the number of addresses is insufficient, resulting in IP address exhaustion.
Temporary fixes have been put in place, such as IP pooling, however a long term solution was still needed. This was the reason for the development and rollout of IPv6
Internet Protocol Version 6
Example:2001:0db8:85a3:0000:0000:8a2e:0370:7334
IPv6, short for Internet Protocol version 6, is the successor to IPv4 (Internet Protocol version 4) and is designed to overcome the limitations of IPv4, primarily the exhaustion of available IP addresses.
The key new features of IPv6 are:
- Expanded address space
- Hexadecimal notation
IPv6 uses 128-bit addresses which means there are 2^128 (about 340 undecillion) possible unique IPv6 addresses.
IPv6 Address Structure
2001:0db8:85a3:0000:0000:8a2e:0370:7334
- Addresses are 128 Bits Long
- Written in Hexadecimal
- Split Intro 8 sections of 4 bits
- Separated by Colons
Which of the following is a valid IPv6 address?
IPv6 Address Compression
To simplify addresses, IPv6 allows for certain abbreviations, such as omitting leading zeros and using double colons (::) to represent consecutive groups of zeros. This is known is address compression.
Example
Full IPv6 Address: 2001:0db8:0000:0000:0000:0000:0000:0042
Compressed IPv6 Address: 2001:db8::42
Full details on how to compress addresses can be found here.
Introduction to MAC Addresses
Example : 00:1A:2B:3C:4D:5E
Media Access Control addresses are physical addresses that uniquely identify network interfaces, such as network interface cards (NICs) in computers and other devices that connect to a network. They are used by switches to send frames within networks.
They function at the:
- The data link layer of the TCP/IP Model
- The link layer (layer 2) of the OSI Model
What is the primary purpose of a MAC address in networking?
MAC Address structure
Example : 00:1A:2B:3C:4D:5E
- Usuallly 48 bits
- Written in hexadecimal
- 6 sections of 2 digits
- Separated by a semicolon or hypen.
Which of the following formats correctly represents a MAC address?
MAC Address Assignment
MAC addresses are assigned by the manufacturer of the network interface card.
The first half of the MAC address (24 bits) is known as the OUI (Organizationally Unique Identifier), which is assigned to the manufacturer by the IEEE (Institute of Electrical and Electronics Engineers).
The second half is assigned by the manufacturer to uniquely identify each NIC they produce.
MAC address spoofing
MAC address spoofing is a technique used to change or falsify the Media Access Control (MAC) address of a network interface. This process involves modifying the MAC address of a network adapter, such as a network card or a wireless interface, to impersonate another MAC address.
This can be used for legitimate & malicious purposes:
- Increased privacy
- Bypassing network controls (such as 15 minute free internet access in airports)
- Performing Man In The Middle (MITM) attacks on routers or other devices.
Is it possible to change the MAC address of a network device?
Review: Fill in the Blanks
Each IPv4 address consists of 32 bits, which enables approximately 4.3 billion unique addresses. These addresses are typically represented as four decimal numbers, separated by , and each part is 8 bits long with values ranging from 0 to . Public IP addresses are unique identifiers that are crucial for routing data between devices on the internet and can be either or .
Private IP addresses, in contrast, are used within local networks like home or business intranets and are not globally routable. They provide security by keeping internal devices hidden from the , and communication with the internet requires the use of (NAT). Due to the limited number of available addresses, IPv4 faces , prompting the development of IPv6 to accommodate the growing need for more unique addresses.
Complete! Ready to test your knowledge?
IPv4
- Introduction to IPv4
- IPv4 Address Structure
- Public IP Addresses
- Private IP Addresses
- IP Address Exhaustion
IPv6
- Internet Protocol Version 6
- IPv6 Address Structure
- IPv6 Address Compression
MAC Addresses
- Introduction to MAC Addresses
- MAC Address structure
- MAC Address Assignment
- MAC address spoofing