Everything You Need to Know About IPv6: The Latest Internet Protocol

Updated on December 19, 2022
Everything You Need to Know About IPv6: The Latest Internet Protocol

What is IPv6, and what does it stand for?

IPv6, where IP stands for Internet Protocol and v6 for Version Six (IPv6). After IPv4 was brought into action for production within the ARPANET in 1983, (IETF) Internet Engineering Task Force created the newest version called IPv6. It helps improve performance and identify the local endpoint systems on a computer network and other online traffic routes. It also addresses the problem of IPv4 address exhaustion due to a large number of internet users worldwide. IPv6 features are more advanced and secure.

IETF developed IPv6 to accommodate the growing urgency for more unique IP addresses. There’s a possibility that we might run out of IPv4 addresses very soon—without an alternative—which may cause severe consequences in the future. IPv6 is the successor to IPv4 and was designed to supplement and ultimately replace version 4, though total adoption of version 6 is still a ways off.

IPv6 became a standard draft version for the IETF in December 1998, and in July 2017, it got approved as an internet standard for global rollout. We call it the future of next-generation protocol.

How is IPv6 better than IPv4?

One of the main factors for the development of IPv6 was to find solutions and overcome the problem of IPv4 addressing lack of capacity & its exhaustion. By keeping such factors in mind, the IETF also optimized the protocol in the general sense.

IPv4 and IPv6 addresses function similarly in allowing devices connected to the internet to communicate, and that’s where their similarities end. If we talk about IPv6 first, it is a 128-bit address. IPv4, on the other hand, is only 32-bit. The header structure of each address differs as well. IPv6 also has less overhead processing and eliminates the need for Network Address Translation (NAT), as address space isn’t a problem. We also discovered that IPv6 is far more compatible with mobile networks than IPv4, making it more efficient. IPv4 allows around 4.2 Billion unique IP addresses. However, IPv6, on the other side, allows 3.4 x 1038 unique IP addresses. This is equal to 340 trillion (x3) IP addresses, which is indeed a lot.

To read more about the differences between IPv4 and IPv6, check out our detailed IPv4 vs. IPv6 guide.

How does IPv6 work?

  • With 128-bit (2128) addresses, IPv6 offers 3.4 x 1038 unique IP addresses or 340 trillion addresses.
  • In hexadecimal notation, IPv6 is divided into 8 groups of 16 bits each, for a total of 128 bits (8 x 16). This is how an IPv6 address is represented:


  • DHCPv6 or Stateless Address Auto Configuration (SLAAC) can be used to configure IPv6 manually.
  • A fixed 40-byte base header and 1240 bytes of payload are the minimum packet sizes for IPv6 (user data).
  • Many operating systems, including Windows, Linux, macOS, Solaris, and BSD, also support IPv6.

Types of IPv6 addresses

IPv6 addresses are categorized into three basic types; Unicast, Multicast & Anycast.


This specific address type holds the most important role in the IPv6 ecosystem. It differentiates itself by these sub-type Global Unique Addresses, which are globally reachable and designed for use on any network out there;



Loopback address: in the IPv4 version, this address is denoted as: but we abbreviate it further in IPv6 as; “::1/128”

Unique local addresses: The scope of this address’s reachability is restricted to within the organization. In IPv6, this address is written as:


Link-local addresses: Important and required on every IPv6-enabled interface, but its packets cannot exit or enter the interface, making it for local use only. Routers do not forward packets with a destination or source address containing this specific address. A link-local address is majorly used by software applications and starts with:



The multicast address allows you to send data packets from multiple sources simultaneously to various other receivers. Along with specifying a set of interfaces at multiple locations, a packet delivered to a multicast group always has a unicast source address.

The range of a multicast address is ff00::/8. In this range, the first 8 bits will always be ff.


Almost identical to Multicast addresses, Anycast addresses differ only in a few key respects. It defines a group of different geographic interfaces that communicate with one another over a common address. Any data supplied to an anycast address is delivered exclusively to the closest member of the cluster.

Which of these ipv6 address types are best used for hosts that are reachable from the internet?

Global unicast Addresses are best for hosts because they are globally reachable and routable. This particular address plays an essential role in the IPv6 addressing architecture. One of the primary motivations for transitioning to IPv6 is the exhaustion of its IPv4 counterpart.

IPv6 features

Following is the list of features of IPv6;

End-to-end connectivity

Every system specifies information processing addresses that may pass through the web while not mistreating NAT or alternative translating elements. Once IPv6 is enforced, each host will directly reach alternative hosts on the web, with some limitations like Firewalls, organization policies, etc.

Enhance Qos support

A vital advantage of the larger packet header is the ability to implement Quality of Service (QoS) technologies. The IPv6 packet header contains fields that facilitate the support for QoS for each differentiated and integrated service.


It allows stateless address configuration (which means no dynamic host configuration protocol DHCP server) and stateful address configuration to make the host set-up easy. It hosts a connection that automatically manages IPv6 addresses for the link, using them to generate via prefixes that local routers announce during stateless address settings. It ensures that inter-communication continues to go on regardless of the presence of a server.

No Broadcast/Multicast

IPv6 supports multicast rather than broadcast. Multicast permits bandwidth-intensive packet flows to be delivered to multiple destinations simultaneously, saving network information measures. IPv6 doesn’t have any communication support to any extent further. It utilizes multicast to talk with numerous hosts.


IPv6 was designed while keeping mobility in mind. This feature empowers hosts to roam around different geographical areas and remain connected to the same IP address. It’s possible due to IPv6’s auto IP arrangements feature and Extension headers feature that enables a user/host to stay free from the pain of taking care of the IP of their device and can remain connected to the network.

Advantages of IPv6:

Following are some notable advantages of IPv6:

1)   Systematic Routing

Since IPv6 fragmentation requires grouped address allocation generated for effective routing, it is performed at the source device rather than at a router.

2)   Greater Capacity

Compared to IPv4 addressing, IPv6 offers larger address space because it is based on a 128-bit addressing method. The network and host components are twice as long.

3)   No subnetting

By utilizing automated configuration, IPv6 eliminates the issues associated with subnetting. Static IP addresses were replaced with automatic configurations.

4)   Safer & secured

Safer and more secure than IPv4, IPSec security uses Authentication Headers (AH), which have built-in authentication mechanisms for network firewalls. Being an AstrillVPN user, you can also test IPv6 leaks to ensure you’re safe online.

AstrillVPN has a dedicated IPv6 leak testing tool that allows users to check whether there’s an IP leak. If you are using IPv6, you can try it and ensure your safety.

5)   Efficient Data flow

Large data packets can be transferred simultaneously using IPv6, which will benefit us.

Disadvantages of IPv6

Following are some notable disadvantages of IPv6:

1)   Gradual adaptation

Since many users are still configured to use IPv4, the transition to IPv6 will take some time because it is a slower procedure.

2)   Topology support

Just because an IPv6 module has additional space, fixing prefixes on the majority of topology designs is difficult when using the IPv6 protocol.

3)   IP scheme conversion

The migration from IPv4 to IPv6 is a slow and difficult process because there is no backward compatibility. In addition, switching between multiple protocols costs the Internet Service Provider (ISP) money.

4)   Readability

It can be challenging to learn and adjust to IPv6 subnetting. Additionally, given the length of your IPv6 address, it may be challenging to remember.


IPv6 is indeed beneficial, with great features & protocols. However, it will take us some time to completely move from IPv4 and commit to IPv6. I hope this article helped you learn about its full potential.


1.   Which type of ipv6 address is unique throughout the ipv6 universe?

The Global Unicast addresses (GUAs) are unique & globally identified through the IPv6 universe.

2.   How many unique IP addresses could be made in a fixed-length IP address system using 6 bits?

IPv6 uses 128-bit (2128) addresses, allowing 3.4 x 1038 unique IP addresses. This is equal to 340 trillion IP addresses. It has hexadecimal notations, and it can be configured manually.

3.   Which IPv6 header field is known as the priority field?

The traffic class field is known as the priority field, as the size of this field is 8 bits. The functionality provided by this field is similar to the one provided by the IPv4 addresses.

4.   Which ipv6 address type can be used to communicate with any ipv6 device?

The link-local address type can be used to communicate with any IPv6 device. However, it only allows the devices connected to the same subnet mask to communicate.

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About The Author

Arsalan Rathore

Arsalan Rathore is a tech geek who loves to pen down his thoughts and views on cybersecurity, technology innovation, entertainment, and social issues. He likes sharing his thoughts about the emerging tech trends in the market and also loves discussing online privacy issues.

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