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IPv6 SEO Hosting Guide

What is IPv6?

Internet Protocol Version 6 (IPv6) is a network layer protocol which allows communication and data transfers to take place over the network. IPv6 protocol, which is 128-bits, consists of eight numbered strings, each containing four characters (alphanumeric), separated by a colon. This gives us an unbelievable amount of unique IP addresses; 340,282,366,920,938,463,463,374,607,431,768,211,456 to be precise.

An example of an IPv6 address is:


Why do we need it?

The most obvious technical answer is that IPv4 is out of IP addresses. IPv4 has only 4.3 billion addresses, and even if not all of them are already assigned to different devices, we soon reach a point that there are no more IPv4 available.

There have been many attempts to make better use of IPV4 space. Options like NAT and re-subnetting is widely used but still, IPv6 is the only solution which truly solves the IPv4 address exhaustion problem, and should be deployed as widely and as soon as possible.

In addition to IPv4 space exhaustion, we believe there are potential SEO benefits of having your websites on both IPv4 and IPv6.


It is important to be mindful of footprint and source isolation in IPv6 as much as is the case with IPv4 for all SEO purposes.

What are the SEO benefits of IPv6?

There are many signs that IPv6 could help different websites and even make PBN more valuable:

  • Google might give sites that have IPv6 address boost for searches coming from visitors that have IPv6 (In the US alone that is more than 30% of visitors)

  • Many of the top 10,000 sites on Alexa 1 million list are available on IPv6 (Google, youtube, Netflix and so on). There is a good chance for a website to be on both IPv4 and IPv6 if the site is maintained by a big corporate. While on another hand all SPAM websites and content farms are on IPv4 only. Google AI, sees IPv6 as a quality factor.

  • Google deindexing seems so far to have only affected domains that are on single IPv4.

  • From our own experience enabling IPv6 on our backlogs and our main sites have improved our SERP.

  • In the second half of 2018, Google finally enabled IPv6 on all its cloud offering. We expect that Google and in the coming years publicly announces IPv6 as a ranking factor the same way they made a similar announcement for SSL. That could be a significant push by Google to boost IPv6 adoption (Similar to what they did with SSL). The websites that have been on IPv6 for a long time are going to enjoy from this ranking factor the most.

Why a serious SEO agency should invest in IPV6?

  • The PBN is going to be more valuable.
  • The backlinks are going to coming from both IPv4 and IPv6.
  • The PBN is going to look more mature and thoughtfully designed to Google
  • The chances of wrongfully flagged as SPAM is going to be lower
  • There are ranking boosts
  • The IPv6 visitors can access the website on your IPv6(more than 35% of US traffic alone is on IPV61) .

IPv6 address Format explained

IP version 6 (IPv6) includes the following types of addresses:

  1. Unicast: A unicast address specifies an identifier for a single interface to which packets are delivered (Similar to public IPv4 addresses). IPV6 Address Format
  2. Multicast: A multicast address specifies an identifier for a set of interfaces that typically belong to different nodes. It is identified by a value of 0xFF. IPv6 multicast addresses are distinguished from unicast addresses by the value of the high-order octet of the addresses. The devices support only host-inbound and host-outbound multicast traffic. Host inbound traffic includes logging, routing protocols, management traffic, and so on.
  3. Anycast: An anycast address specifies an identifier for a set of interfaces that typically belong to different nodes. A packet with an anycast address is delivered to the nearest node, according to routing protocol rules.

IPv6 address shortening

IPv6 addresses can be shortened. Let’s take a look at some examples:


  • If there is a string of zeros then you can remove them once. In the example above we removed the entire 0000:0000:0000 part resulting in and empty ::. You can only do this once, and the IPv6 device will fill up the remaining space with zeros until it has a 128 bits address.

  • There is more, the address can be shortened even more:


  • If you have a “hextet” with 4 zeros then you can remove those and leave a single zero. Your IPv6 device will add the remaining 3 zeros.


When we talk about IPv4 addresses, we use the term “octet” to define a “block” of 8 bits. In IPv6, there is no official term (yet), and there is an IETF draft that discusses the names to be used. The official term for 4 hexadecimal values is “hexadectet”, this is hard to remember/pronounce so the short form “hextet” will be used.

  • Leading zeros can also be removed, here’s another address to demonstrate this:


By removing these zeros we get a nice short IPv6 address.

To summarize these rules:

  1. An entire string of zeros can be removed and replace them with ::, you can only do this once.
  2. 4 zeros can be removed, leaving only a single zero.
  3. Leading zeros can be removed.

What are the SEO classes of an IPv6 address?

Unlike IPv4 there is no official address class definition for IPv6 classes. It is important to remember that Google already has invested significantly in IPv6 space and that Google has some IPv6 related patents which cover a wide range of topics from tunneling and communication to mobile communication and cases IPv6 only networks2, we need to apply the same concepts as IPv4 to IPv6.

This is mostly to help SEO experts familiarise themselves with the new IP spec. After all the logic remains the same, the backlinks that come from unrelated networks pass more juice and are more natural looking.


The IPv6 SEO class definition provides a good level of separation on each class level. It also avoid scenarios in which a single datacenter become a sole provider of IPV6 SEO B-class IPs.

Similar to IPv4 SEO IPs we define four different classes: A, B, C, and D. Unlike IPv4, the concept of “Class” is not already a part of the protocol. In IPv6 space instead of class here we have prefixes.

There are many different guidelines on IPv6 assignment. One preferred mechanism is to give away /48 prefixes to end sites (Companies, building blocks and so on) and then assign /64 or smaller allocations to end users.

After careful review of IPv6 assignments across the world we came to the following classifications:

IPV6 SEO Classes

  1. For different A-class IPs should have different /32 prefixes.
  2. For different B-class IPs should have different /36 prefixes.
  3. For different C-class IPs should have different /40 prefixes.
  4. For different D-class IPs should have different /48 prefixes.


At the moment we do not sell different D-Class to our clients, as we are not yet sure if that assignment comes with zero-footprint

How to compare 2 IPv6 classes?

Now that we know how IPv6 is formatted it is easy to compare the IPs by following these steps:


  1. If the address is in short format expand it to the long format (32 digits with all the zeros).
  2. From the left compare the first 8 digits. If the values are all equal both IPv6 addresses are on the same /32 prefix (They are on the same A-Class) otherwise they are on different A-Class
  3. From the left compare the first 9 digits. If the values are all equal both IPv6 addresses are on the same /36 prefix (They are on the same B-Class) otherwise they are on different B-Class
  4. Now from the left compare the first 10 digits*. If the values are all equal both IPv6 addresses are on the same /40 prefix (They are on the same C-Class**) otherwise they are on different C-Class
  5. Finally, from the left compare the first 12 digits. If the values are all equal both IPv6 addresses are on the same /48 prefix (They are on the same D-Class) otherwise they are on different D-Class

Let’s try the above formula on two different IPv6 addresses:

  • First let’s expand the above IPs:
  • Now let's check their A, B and C classes:

  • A-Class (/32 = 8 digits)


As we can see they share the same A class * B-Class (/36 = 9 digits)


As we can see they share the same B class

  • C-Class (/40 = 10 digits)

As we can see the IPs are on different C classes.

How to Order IPv6?

Here are Smart SEO Hosting, you may order additional SEO IPv6 from different A, B and C classes and from all around the world.

The IPv6 packages are incredibly affordable and can be ordered from the IPv6 SEO Hosting section.

  1. Source: 

  2. A Google patent search for all patents owned to Google umbrella companies, shows 1740 results.