IPv6 and IPv4
IPv4 vs IPv6: What’s the Difference Between IPv4 and IPv6?
What is IP?
An IP (Internet Protocol) address is a numerical label assigned to each device connected to a computer network that uses the IP protocol for communication. An IP address acts as an identifier for a specific device on a particular network. The IP address is also called an IP number or Internet address.
IP address specifies the technical format of the addressing and packets scheme. Most networks combine IP with a TCP (Transmission Control Protocol). It also allows developing a virtual connection between a destination and a source.
Now in this IPv4 and IPv6 difference tutorial, we will learn What is IPv4 and IPv6?
What is IPv4?
IPv4 is an IP version widely used to identify devices on a network using an addressing system. It was the first version of IP deployed for production in the ARPANET in 1983. It uses a 32-bit address scheme to store 2^32 addresses which is more than 4 billion addresses. It is considered the primary Internet Protocol and carries 94% of Internet traffic.
What is IPv6?
IPv6 is the most recent version of the Internet Protocol. This new IP address version is being deployed to fulfill the need for more Internet addresses. It was aimed to resolve issues that are associated with IPv4. With 128-bit address space, it allows 340 undecillion unique address space. IPv6 is also called IPng (Internet Protocol next generation).
Internet Engineer Taskforce initiated it in early 1994. The design and development of that suite are now called IPv6.
IPv4 is 32-Bit IP address whereas IPv6 is a 128-Bit IP address.
IPv4 is a numeric addressing method whereas IPv6 is an alphanumeric addressing method.
IPv4 binary bits are separated by a dot(. ) whereas IPv6 binary bits are separated by a colon(:).
IPv4 offers 12 header fields whereas IPv6 offers 8 header fields.
IPv4 supports broadcast whereas IPv6 doesn’t support broadcast.
IPv4 has checksum fields while IPv6 doesn’t have checksum fields
When we compare IPv4 and IPv6, IPv4 supports VLSM (Variable Length Subnet Mask) whereas IPv6 doesn’t support VLSM.
IPv4 uses ARP (Address Resolution Protocol) to map to MAC address whereas IPv6 uses NDP (Neighbour Discovery Protocol) to map to MAC address.
Features of IPv4
Following are the features of IPv4:
Allow creating a simple virtual communication layer over diversified devices
It requires less memory, and ease of remembering addresses
Already supported protocol by millions of devices
Offers video libraries and conferences
Features of IPv6
Here are the features of IPv6:
Hierarchical addressing and routing infrastructure
Stateful and Stateless configuration
Support for quality of service (QoS)
An ideal protocol for neighboring node interaction
IPv4 vs IPv6
Difference Between IPv4 and IPv6 Addresses
IPv4 & IPv6 are both IP addresses that are binary numbers. Comparing IPv6 vs IPv4, IPv4 is 32 bit binary number while IPv6 is 128 bit binary number address. IPv4 address are separated by periods while IPv6 address are separated by colons.
Both are used to identify machines connected to a network. In principle, they are the same, but they are different in how they work. Below are the main differences between IPv4 and IPv6:
Basis for differences
Size of IP address
IPv4 is a 32-Bit IP Address.
IPv6 is 128 Bit IP Address.
IPv4 is a numeric address, and its binary bits are separated by a dot (. )
IPv6 is an alphanumeric address whose binary bits are separated by a colon (:). It also contains hexadecimal.
Number of header fields
Length of header filed
Has checksum fields
Does not have checksum fields
12. 244. 233. 165
Type of Addresses
Unicast, broadcast, and multicast.
Unicast, multicast, and anycast.
Number of classes
IPv4 offers five different classes of IP Address. Class A to E.
lPv6 allows storing an unlimited number of IP Address.
You have to configure a newly installed system before it can communicate with other systems.
In IPv6, the configuration is optional, depending upon on functions needed.
IPv4 support VLSM (Variable Length Subnet mask).
IPv6 does not offer support for VLSM.
Fragmentation is done by sending and forwarding routes.
Fragmentation is done by the sender.
Routing Information Protocol (RIP)
RIP is a routing protocol supported by the routed daemon.
RIP does not support IPv6. It uses static routes.
Networks need to be configured either manually or with DHCP. IPv4 had several overlays to handle Internet growth, which require more maintenance efforts.
IPv6 support autoconfiguration capabilities.
Widespread use of NAT (Network address translation) devices which allows single NAT address can mask thousands of
non-routable addresses, making end-to-end
It allows direct addressing because of vast address
Use for the designated network from host portion.
SNMP is a protocol used for system management.
SNMP does not support IPv6.
Mobility & Interoperability
Relatively constrained network topologies to which move restrict mobility and interoperability capabilities.
IPv6 provides interoperability and mobility
capabilities which are embedded in network devices.
Security is dependent on applications – IPv4 was not designed with security in mind.
IPSec(Internet Protocol Security) is built into the IPv6 protocol, usable with
a proper key infrastructure.
Packet size 576 bytes required, fragmentation optional
1208 bytes required without fragmentation
Allows from routers and sending host
Sending hosts only
Does not identify packet flow for QoS handling which includes checksum options.
Packet head contains Flow Label field that specifies packet flow for QoS handling
Address (A) records, maps hostnames
Address (AAAA) records, maps hostnames
Manual or via DHCP
Stateless address autoconfiguration using Internet Control Message Protocol version 6 (ICMPv6) or DHCPv6
IP to MAC resolution
Multicast Neighbour Solicitation
Local subnet Group management
Internet Group Management Protocol GMP)
Multicast Listener Discovery (MLD)
Has Optional Fields
Does not have optional fields. But Extension headers are available.
Internet Protocol Security (IPSec) concerning network security is optional
Internet Protocol Security (IPSec) Concerning network security is mandatory
Dynamic host configuration Server
Clients have approach DHCS (Dynamic Host Configuration server) whenever they want to connect to a network.
A Client does not have to approach any such server as they are given permanent addresses.
Uses ARP(Address Resolution Protocol) to map to MAC address
Uses NDP(Neighbour Discovery Protocol) to map to MAC address
Combability with mobile devices
IPv4 address uses the dot-decimal notation. That’s why it is not suitable for mobile networks.
IPv6 address is represented in hexadecimal, colon- separated notation.
IPv6 is better suited to mobile
IPv4 and IPv6 cannot communicate with other but can exist together on the same network. This is known as Dual Stack.
6in4 – Wikipedia
6in4 is an IPv6 transition mechanism for migrating from Internet Protocol version 4 (IPv4) to IPv6. It is a tunneling protocol that encapsulates IPv6 packets on specially configured IPv4 links according to the specifications of RFC 4213. The IP protocol number for 6in4 is 41, per IANA reservation. 
The 6in4 packet format consists of the IPv6 packet preceded by an IPv4 packet header. Thus, the encapsulation overhead is the size of the IPv4 header of 20 bytes. On Ethernet with a maximum transmission unit (MTU) of 1500 bytes, IPv6 packets of 1480 bytes may therefore be transmitted without fragmentation.
6in4 tunneling is also referred to as proto-41 static because the endpoints are configured statically. Although 6in4 tunnels are generally manually configured, the utility AICCU can configure tunnel parameters automatically after retrieving information from a Tunnel Information and Control Protocol (TIC) server.
The similarly named methods 6to4 or 6over4 describe a different mechanism. The 6to4 method also makes use of proto-41, but the endpoint IPv4 address information is derived from the IPv6 addresses within the IPv6 packet header, instead of from static configuration of the endpoints.
Network address translators
When an endpoint of a 6in4 tunnel is inside a network that uses network address translation (NAT) to external networks, the DMZ feature of a NAT router may be used to enable the service.  Some NAT devices automatically permit transparent operation of 6in4.
Dynamic 6in4 tunnels and heartbeat
Even though 6in4 tunnels are static in nature, with the help of for example the heartbeat protocol one can still have dynamic tunnel endpoints. The heartbeat protocol signals the other side of the tunnel with its current endpoint location. A tool such as AICCU can then update the endpoints, in effect making the endpoint dynamic while still using the 6in4 protocol. Tunnels of this kind are generally called ‘proto-41 heartbeat’ tunnels.
The 6in4 protocol has no security features, thus one can inject IPv6 packets by spoofing the source IPv4 address of a tunnel endpoint and sending it to the other endpoint. This problem can partially be solved by implementing network ingress filtering (not near the exit point but close to the true source) or with IPsec.
The mentioned packet injection loophole of 6in4 was exploited for a research benefit in a method called IPv6 Tunnel Discovery  which allowed the researchers to discover operating IPv6 tunnels around the world.
RFC 1933, Transition Mechanisms for IPv6 Hosts and Routers, R. Gilligan and E. Nordmark, 1996
RFC 2893, Transition Mechanisms for IPv6 Hosts and Routers, R. Nordmark, 2000
RFC 4213, Basic Transition Mechanisms for IPv6 Hosts and Routers, R. Nordmark, 2005
List of IPv6 tunnelbrokers
^ “Protocol Numbers”.
^ Heartbeat Protocol, J. Massar and P. van Pelt
^ IPv6 Tunnel Discovery, L. Colitti, G. Di Battista, and M. Patrignani
How do I configure my machine to set up an IPv6 in IPv4 tunnel
6in4 and other tunnel setups on Debian
6in4 setup on Plan9 OS
Frequently Asked Questions (FAQ) on IPv6 adoption and IPv4 exhaustion
There have been several calls to action for organisations to deploy the newer version of the Internet Protocol, IPv6, which is designed to eventually replace the IPv4 protocol. The Internet Society strongly supports such calls for action. In fact, the Internet Society-led World IPv6 Launch on 6 June 2012 was a major catalyst for IPv6 deployment.
If deployment is delayed, the future growth and global connectivity of the Internet will be negatively impacted. The information below is intended to assist in answering some of the frequently asked questions associated with exhaustion of the IPv4 address pool and the adoption of IPv6.
This list of FAQs is intended to be a “living document. ” It will continue to be updated and expanded. In addition, read these additional documents:
NEW: IPv6 Security Frequently Asked Questions (FAQ)
Who Makes the Internet Work? The Internet Ecosystem
A short Guide to IP Addressing
Table of Contents
Is the Internet about to run out of IPv4 addresses?
What is IPv6?
Who created IPv6 and how long has IPv6 been available?
What happened to IPv5??
How does IPv6 solve the problem of IPv4 address exhaustion?
What happens when the IPv4 address pool is finally depleted?
When will IPv4 addresses actually run out?
What’s the difference between IPv4 and IPv6? Will users be able to tell the difference?
I’ve heard some people say IPv6 is more secure than IPv4, while others say it is less secure than IPv4. What is this about?
Is IPv6 ready for deployment now?
Why has it taken so long for IPv6 to be implemented?
Has IPv6 been added to the root servers?
How much will the transition to IPv6 cost?
I have enough IPv4 addresses today. Why should I bother implementing IPv6?
Is there a specific date when everything needs to be upgraded to IPv6?
Will IPv6 addresses run out eventually?
When will I need to turn off IPv4?
Will IPv4 address depletion mean that services will get switched off?
Isn’t address sharing the answer? We introduced NAT last time addresses were becoming scarce.
Without NAT, won’t my network be less secure?
I run an ISP with a block of IPv4 address space. Can I just convert that into IPv6 space?
I run IT services. What should I be doing now to get ready?
A qualified ‘yes’ to this.
As of October 2018, all the RIRs are assigning addresses from their last /8 block. An up-to-date report on IPv4 address assignment can be found here.
To put IPv4 address exhaustion into perspective, there are an estimated 11 billion devices connected to the Internet (Gartner), and this number is estimated to increase to 20 billion by 2020. There are also estimated to be 3. 2 billion Internet users in the world (ITU), but the global population is 7. 2 billion, so it is clear there are insufficient public IPv4 addresses to service future requirements. It is currently expected that the public IPv4 address pool will be entirely depleted by 2021.
There is a substantial amount of IPv4 address space (so-called legacy addresses) that was previously assigned to organisations and never used, or were assigned for experimental purposes and are no longer required. Some of this has been returned or recovered by IANA who in turn re-allocates it to the RIRs, whilst Local Internet Registries (LIRs) are also able to trade IPv4 address blocks that exceed requirements to other LIRs, therefore encouraging more efficient usage. The typical cost of a /24 block of 255 addresses is currently in the order of USD $12-14 per address (IPv4 Market Group).
Another widely used technique to facilitate connectivity is Network Address Translation (NAT), which uses specifically allocated IPv4 blocks (typically 10. x. x or 192. 168. x) that are reserved for private networks. This allows nodes to use private IPv4 addresses in the internal network, while sharing a single public IPv4 address when communicating with the public Internet. However, NAT requires IP packets to be rewritten by a router, which can impose a performance penalty and cause problems with certain higher level protocols that employ IPv4 address literals (as opposed to domain names) in the application protocol. Some large ISPs that are running Carrier-Grade NAT (CGN) are also finding that even the 16. 7 million addresses available in the largest private IPv4 block are insufficient to service their customers, and are therefore having to run multiple layers of CGN which causes substantial performance and network management issues.
In the European (served by RIPE NCC) and North American (served by ARIN) regions, IPv4 addresses are no longer freely available and there is a wait list () for recovered addresses. The Asia-Pacific (APNIC) and Latin America and the Caribbean (LACNIC) regions have implemented strict rationing measures to conserve availability whereby new LIRs are only eligible for a /22 block of 1, 024 addresses, with only the African (AfriNIC) region not considered to have depleted their address pool.
The Internet Society, ICANN, and the RIRs encourage network operators to adopt IPv6, which enables 340 trillion trillion trillion IP addresses to be used. That’s enough for millions of addresses to be assigned to every person on Earth for hundreds of years, and solves the problem of an insufficient number of IPv4 addresses to meet the needs of a growing Internet.
IPv6 is a new version of the Internet Protocol that will eventually replace IPv4, the version that is most widely used on the Internet today. IPv6 is a well established protocol that is seeing growing usage and deployment, particularly in mobile phone markets.
IPv6 was created by the Internet Engineering Task Force (IETF), an international group that develops technical standards for the Internet. The core specification for the IPv6 protocol was first published in 1995 as RFC 1883, and has seen a number of enhancements and updates since then. It formally became a full standard (as opposed to a draft standard) in 2017 with the publication of RFC 8200, although IPv6 had already been deployed for many years.
What happened to IPv5?
Version 5 of the IP family was an experimental protocol developed in the 1980s. IPv5 (also called the Internet Stream Protocol) was never widely deployed, and since the number 5 was already allocated, this number was not considered for the successor to IPv4. Several proposals were suggested as the IPv4 successor, and each was assigned a number. In the end, the one with version number 6 was selected.
IPv6 uses 128-bit addresses as opposed to the 32-bit addresses used by IPv4, allowing for a substantially larger number of possible addresses. With each bit corresponding to a ‘0’ or ‘1’, this theoretically allows 2^128 combinations or 340 trillion, trillion, trillion addresses. By contrast, IPv4 permits 2^32 combinations for a maximum of approximately 4. 7 billion addresses.
In practice, the actual number of usable addresses is slightly less as IPv6 addresses are structured for routing and other purposes, whilst certain ranges are reserved for special use. The number of IPv6 addresses available, though, is still extremely large.
Network operators and large enterprises are typically expected to be assigned a /32 address block, smaller enterprises a /48, and home users a /56 (when they would typically get a single IPv4 address). This allows for scalability and future subnetting, and a virtually-unlimited number of addresses in each /64 subnet.
There is an erroneous perception that the assignment of large IPv6 prefixes to end customers is wasteful, but the IPv6 address space is so huge that it has been calculated (by Tony Hain) that a /48 could be assigned to every human for the next 480 years before they run out.
Existing devices and networks connected to the Internet using IPv4 addresses should continue to work as they do now. In fact, IPv4-based networks are expected to co-exist with IPv6-based networks at the same time.
However, for network operators and other entities that rely on Internet address assignments, it will become increasingly difficult and expensive (and eventually prohibitively so) to obtain new IPv4 address space to grow their networks. The cost and complexity associated with keeping track of and managing remaining IPv4 address space efficiently will also increase, so network operators and enterprises will need to implement IPv6 in order to ensure long-term network growth and global connectivity.
There are various translation mechanisms available to allow hosts that support only IPv4 or IPv6 to communicate with each other. For example, NAT64 facilitates communication using a form of Network Address Translation (NAT) whereby multiple IPv6 addresses can be mapped onto one IPv4 address, thus allowing traffic using the different protocols to be exchanged while conserving IPv4 address space. NAT64 uses a gateway that routes traffic from an IPv6 network to an IPv4 one, and performs the necessary translations for transferring packets between the two networks. 464XLAT extends this functionality by allowing IPv4-only applications to communicate over a IPv6-only network, making an IPv4 address unnecessary on the host device.
Many well-known enterprises are already deploying IPv6-only services and networks, which reduces the network management burden as there is no longer any IPv4 on the network. The need to translate from an IPv6-only environment to IPv4-only hosts on the Internet will reduce as IPv6 is more widely deployed around the world.
Of course, it will still be possible to use existing IPv4 addresses for the foreseeable future, even though their usage is expected to decline as devices and services increasingly support IPv6.
The last IPv4 address blocks have already been allocated to the Regional Internet Registries (RIRs) and have either been depleted or are very close to depletion. Some legacy address blocks may be recovered and reallocated, and some previously assigned address blocks will be traded by their holders, but it will no longer be possible to get new address blocks to meet the future growth of the Internet. An up-to-date report on IPv6 assignment is available here.
The key difference between the versions of the protocol is that IPv6 has significantly more address space. Users should not be aware of any difference.
The addresses do look different though. The IPv6 address notation is eight groups of four hexadecimal digits with the groups separated by colons, for example 2001:db8:1f70:999:de8:7648:3a49:6e8, although there are methods to abbreviate this notation. For comparison, the IPv4 notation is four groups of decimal digits with the groups separated by dots, for example 198. 51. 100. 1.
The expanded addressing capacity of IPv6 will enable the trillions of new Internet addresses needed to support connectivity for a huge range of new devices such as phones, household appliances and vehicles.
Debates concerning IPv4 versus IPv6 security often focus on different aspects of network deployment.
It has been said that IPv6 supports improved security because the IP Security (IPsec) was originally developed for IPv6 and it implementation was intended to be a mandatory part of the protocol. However, IPsec can also be used with IPv4, and is now simply recommended for use with IPv6 because it was considered impractical to require full IPsec implementations for all types of devices that may use IPv6. The benefits of using IPsec are similar with both IPv4 and IPv6.
On the other hand, the increased address space offered by IPv6 does largely eliminate the need to use NAT devices, which are pervasive in many IPv4 networks and implicitly enforce a filtering policy of “only allowing outgoing communications”. As a result, it has been expected that IPv6 would increase host exposure. However, host exposure can be reduce with the use of network firewalls e. g. at the same point of the network topology where one would employ a NAT device (in an IPv4 network).
Many of the reported IPv6 security issues had to do with vulnerabilities in individual products rather than the IPv6 protocol. IPv4 is widely deployed and individual IPv4 products have gone through the recurring cycle of discovering and fixing security vulnerabilities and other bugs. Many IPv6 products are comparatively newer and have fewer users, and have therefore not benefited from similar experience. As with any Internet product, security vulnerabilities will need to be discovered and repaired for IPv6 products.
Operational practices built up over many years for IPv4 networks are being adapted for IPv6, and this will accelerate as more network operators deploy IPv6 and continue to exchange information about experience and best practices through established operator groups, the IETF, and other forums.
Maintaining network security is a challenging undertaking for both IPv4 and IPv6. Neither protocol provides a simple solution to the complexities associated with securing networks, and network operators should familiarise themselves with IPv6 security practices and stay up-to-date with developments as they deploy and operate IPv6.
IPv6 is a tried and tested technology that has been operationally deployed since 2002.
The core IPv6 specifications have benefited from over 20 years of development within the Internet Engineering Task Force (IETF), and have been implemented in many Internet products and services. IPv6 officially became a standard in 2017 (RFC 8200).
IPv6 also includes a large number of individual standards that have a more limited applicability and are only needed in specialised environments, and as with the continuing evolution of IPv4, there will always be updates and additions to IPv6-related specifications in response to deployment-specific experience.
All major operating systems such as Microsoft Windows, MacOS, Linux, iOS and Android support IPv6, more-and-more software applications are IPv6-ready, and those available on Apple’s App Store must be IPv6 capable. Unfortunately, some products and services (including some from major vendors) do not fully support IPv6, and it is best to check with specific vendors on the readiness of their individual products and services, as well as their migration timeline. In addition, in-house software or custom code that interfaces with the network will likely need updating for IPv6.
If developers and vendors have no plans to support IPv6, then it is advisable to look for alternative products and services. Translation mechanisms such as NAT64 and 464XLAT also exist to support IPv4-only services and applications on IPv6 networks.
Operational practices built up over many years for IPv4 networks will have to be adapted for IPv6. Whilst IPv6 has been successfully deployed in production networks for many years, many network operators still have little or no experience in running IPv6. This situation is improving along with the increasing IPv6 deployment, and as experience and best practices are exchanged through the IETF, operator groups and other forums.
The problem was that transitioning to IPv6 did not offer network operators, enterprises, or vendors any clear advantages in the short term, required some expenditure, and was another protocol to manage when few IPv6 services were available. In addition, the introduction of Network Address Translation (NAT) and Classless Internet Domain Routing (CIDR) greatly extended the IPv4 address space to support many more devices without the need for upgrading or replacing them.
However, the IPv4 address space is now close to depletion, it is no longer possible to easily and cheaply obtain more IPv4 addresses, and the complexity of running NATs is starting to outweigh the costs of deploying IPv6. Many ISPs and content providers also now support IPv6, and so the lack of services running on IPv6 is no longer a disincentive to deployment. IPv6 implementation is necessary and no longer something that organisations can put off until tomorrow.
Yes. IPv6 support was incrementally added to the root servers starting with A, F, H, J, K and M on 4 February 2008. The L root server was added on 12 December 2008, with G being the last on 20 October 2016, meaning all 13 root servers are able to support IPv6 queries and responses.
Around 98% of the TLD (Top-Level Domain) servers also support IPv6, and it is an ICANN requirement for all new TLDs to do so.
The costs of transitioning to IPv6 depend on the nature of the organisation and business. All major operating systems, as well as many software applications and hardware devices are IPv6 ready, allowing organisations to deploy it as part of routine upgrade cycles.
For many organisations, operational costs such as training for network/system operators and adding IPv6 to management databases and documentation are likely to constitute the majority of the cost of upgrading to IPv6. Organisations running in-house customised software will have likely have additional costs to upgrade such software to IPv6, whilst enterprises that have test/release processes will see a marginal additional cost for the IPv6 configuration tests.
End-users should not notice when they are using IPv6 instead of IPv4, so there should be no additional training and documentation costs required for them. However, it may be necessary to provide extra training for help desk staff who are required to troubleshoot end user systems running IPv6.
IPv6 is already supported by many major network operators and content providers, and as more and more deploy IPv6, native IPv6 access will not only become the norm, but more sites will only support IPv6. Whilst translation mechanisms exist that allow access to IPv6-only sites for those that only have IPv4, these have an impact on performance and can be difficult to troubleshoot.
It is also worth considering what services and devices may need to be supported over the next few years. Your existing IPv4 address allocations may be insufficient to support a sudden increase in the number of connected devices, as many organisations experienced with the rapid deployment of IP-enabled wireless handheld products and similar devices a few years ago.
There is no specific date when everything must be upgraded to IPv6, although some organisations, including governments, have already identified target dates for their own IPv6 implementation. IPv6 and its transition mechanisms have been designed for a long period of co-existence with IPv4, and it is expected that IPv4-only systems and applications will survive for many years. However, IPv6-only systems are expected to arise and many of these users are likely to be in emerging business markets and developing countries.
Implementing IPv6 requires planning and with the IPv4 address space nearly exhausted, network operators should already be incorporating IPv6 into their upgrade and procurement plans.
You can test your IPv6 readiness here ()
In practical terms, no. There are 2^128 or 340 trillion, trillion, trillion IPv6 addresses, which is more than 100 times the number of atoms on the surface of the Earth. This will be more than sufficient to support trillions of Internet devices for the forseeable future.
Possibly never. The purpose of deploying IPv6 is to ensure network growth and continued interconnectivity when IPv4 address space becomes depleted and difficult to obtain. In addition, as the global Internet continues to expand, it is likely that an increasing number of Internet sites will only be available via IPv6.
To avoid problems, networks and connected devices should be fully IPv6-enabled to take advantage of IPv6-only sites, but IPv4 can co-exist with these until enterprises determine that it is no longer needed or cost effective to maintain. In practice, it may never be cost-effective or possible to upgrade certain legacy systems, but translation mechanisms such as NAT64 and 464XLAT are available to support these for as long as these are required and in use.
No. Both IPv4 and IPv6 will run in parallel until there is no longer any need to do so.
Network Address Translation (NAT) relies on using UDP/TCP port numbers to identify packets sent to one public IPv4 address, but destined for different private IPv4 addresses. These port numbers are 16 bits, which means a theoretical maximum of 65, 535 private IPv4 addresses can be associated with each public IPv4 address. In practice though, a host will have multiple simultaneous traffic flows which means it’s impractical to have more than about 4, 000 hosts behind one public IPv4 address, and will result in reduced performance and increased management complexity.
Some large ISPs are even running into problems with the IPv4 address space reserved for private addresses, as the largest block (10. x) is limited to 16. 7 million addresses. This then means that multiple layers of NAT are required, which further adds to the performance and management complexity issues.
NAT can also cause problems with certain higher level protocols that were designed for end-to-end connectivity or that employ IP addresses in the application data stream, and so should really only be considered a temporary solution. IPv6 needs to be deployed to ensure the Internet continues to perform well and is able to scale into the future.
Translating addresses does not provide any security benefits. In many cases NATs require an outgoing connection to be present before they will allow an incoming connection to succeed. This ‘stateful packet filtering’ can be enabled for IPv6 by means of an IPv6 firewalls.
You will need to obtain new IPv6 addresses from your Regional Internet Registry (RIR). You can keep any IPv4 address space that you have today, and it can still be used in a dual IPv4-IPv6 environment.
The RIRs all have policies that make it straightforward for an ISP with IPv4 space to apply for and receive IPv6 address space. You should contact the RIR for your region, or alternatively your own Internet connectivity provider for more information on how to acquire IPv6 addresses.
It may also be good idea to use this opportunity to redesign your addressing plan, taking advantage of the greater flexibility of IPv6 to assign subscriber address blocks more optimally. Similarly, customer sites may use IPv6 as an opportunity to redesign and optimise their internal addressing plan.
Plan for IPv6 as you would for any major service upgrade.
Do an audit of your current IPv6 capabilities and readiness. Assess the level of IPv6 technical knowledge within your organisation and make plans for staff development and training to support IPv6 implementation.
Think about which of your services will lose business if they are only accessible to IPv4 users and make them a priority for IPv6 capability. For example, you may plan to implement an IPv6-enabled web server for external customers before converting your internal network.
Remove obstacles to enabling IPv6 including identifying any legacy systems that can not be upgraded, and choose a solution for them. Plan upgrades and purchases so that you don’t find that a key system dependency is not IPv6 capable when you do migrate to IPv6.
Contact your vendors to find out about IPv6 support in their current products and future releases and ask your ISP about their plans to support IPv6.
Use the Deploy360 IPv6 Resources for help along the way.
Frequently Asked Questions about ipv6 in ipv4
Does IPv6 work with IPv4?
You will need to obtain new IPv6 addresses from your Regional Internet Registry (RIR). You can keep any IPv4 address space that you have today, and it can still be used in a dual IPv4-IPv6 environment.
What is IPv4/IPv6 settings?
Internet Protocol version 4 (IPv4) is the commonly used form of IP addressing used to identify hosts on a network and uses a 32-bit format. Internet Protocol version 6 (IPv6) is the next-generation IP address standard intended to replace the IPv4 format.Dec 13, 2018
Should I use IPv6 or IPv4?
You should use both IPv4 and IPv6 addresses. Nearly everyone on the Internet currently has an IPv4 address, or is behind a NAT of some kind, and can access IPv4 resources.