IPv6 What it is and why it is important from an Internet of Things perspective
IPv6 What it is and why it is important from an Internet of Things perspective
The so-called ISO/OSI stack represents an internationally recognized reference model that photographs the methods of interconnection between communication systems. The lowest level, the physical one, concerns the methods of transmitting a data flow through the chosen communication medium.
At the third level of the stack are the protocols for interconnecting networks . The Internet Protocol (abbreviated, IP) is what is used on the Internet to interconnect networks that are heterogeneous in terms of technology, performance and management.
Although IPv4 is the version of the Internet Protocol (in another article we talk about the suite of TCP/IP protocols ) that today remains universally more used, IPv6 represents its most recent and advanced incarnation; in the future it will acquire an increasingly important role.
As the Internet Protocol was conceived , each terminal that requests access to the network receives and uses a unique IP address . Whether we speak of a private IP address or a public IP address , respectively for a device connected to the local network or facing the Internet, it uses IPv4, IPv6 addressing or both.
Each terminal connected to the Internet receives a public IP which is assigned by the connectivity provider in a dynamic way (the IP address changes at each connection) or static (the IP is always the same at each subsequent reconnection to the Internet).
Speaking of public IP addresses, this identifier allows you to uniquely recognize a device within the Internet and reach it from anywhere on the planet.
There are of course some exceptions. Some telecommunications operators did not foresee or do not foresee the possibility for customers to use a public IP address (today this almost always happens, at least in the case of connections on the mobile network and for some access offers from a fixed location).
In this case it is said that the network is ” nattata ” or allows communication with the outside world through the NAT ( Network Address Translation ) technique : several users share the same public IP address .
What is IPv6 and why is it needed
For some time now, IPv4 addresses have been exhausted : they remain available to the companies that had requested some blocks for them but in fact the IPv4 addressing space has no free “slots”.
IPv4 uses 32-bit address space for a total of about 232 (4.3 billion) available IP addresses. With the dizzying growth of the network population and the increasingly massive diffusion of client devices used to connect to the Internet on the move, the demand for IP addresses has grown dramatically.
Internet providers that in the past hoarded more or less large blocks of IPv4 addresses are now continuing to manage the dowry of IP acquired in the past.
IPv6 is the solution to the shortage of IPv4 addresses: with IPv6 it is possible to manage globally as many as 2,128 addresses . This is an immense figure, capable of satisfying current and future needs.
Suffice it to say that with IPv6, for every single square meter of the earth’s surface, as many as 660,000 billion billion addresses become available. For comparison, reflect on the fact that, in the case of IPv4, only 7 IPv4 addresses are available for every million square meters. A huge difference.
The Internet of Things market , which has literally exploded in recent years, supports the demand for IP addresses: some devices, such as sensors, industrial equipment, electronic components used at various levels, often need to operate in completely autonomous mode and are connected directly to the Internet network.
Operating systems and routers have already supported IPv6 for years: it is the telecommunications operators who must gradually adapt. New fiber providers did this because, being late to market, they didn’t have large blocks of IPv4 addresses to use so they immediately looked at implementing IPv6.
The table on the state of IPv6 in Italy , published on Fibra.click , clearly indicates which operators support IPv6 and how.
To date, however, Italy is among the European countries where the adoption of IPv6 is slower .
Web-based IPv6 verification allows you to verify if you are using a fully IPv6 compliant provider, network and device .
IPv6: the main characteristics
Think of any local network: that of the company, the office or the home. With IPv4, due to the limitations in terms of assignable addresses, each device in your network cannot use a separate public IP.
Groups of devices connected to the same local network, therefore, take advantage of the aforementioned NAT functionality of the router to send and receive data (the public IP assigned to the router is shared).
If it is necessary to activate server functions on one or more systems connected to the local network (to make a device respond to requests from the Internet), the port forwarding technique must be used .
IPv6 global unicast (GUA) addresses
IPv6 sweeps away all the limitations of IPv4 making it no longer necessary to use NAT and port forwarding techniques .
Each individual device can therefore use, where necessary, its own public IPv6 address and potentially make use of all incoming communication ports .
This happens thanks to IPv6 global unicast addresses : the initial number “2” distinguishes all public addresses today (block 2000::/3 ).
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Even in the case of IPv6 there is the possibility of using private IP addresses within local networks .
In particular, IPv6 private addresses are those defined in RFC 4193 ” Unique Local IPv6 Unicast Addresses “.
Private IPv6 or ULA addresses have the prefix fc00::/7 (the fec0::/10 block is now considered obsolete) with the last 54 bits generated pseudo-randomly.
In general, however, ULA IPv6 addresses are recognizable because they start with fc or fd .
Link-local IPv6 addresses
IPv6 addresses called link-local or ” link-local addresses ” in the Italian translation, are essential for the correct exchange of data within a specific network segment.
Even when no GUA or ULA address is used, link-local addresses still allow the correct flow of data locally, therefore between all the devices connected, for example, with the same router.
If you try to type the command ipconfig /all in Windows you will see, associated with the device in use, a link-local IPv6 address starting with fe80 . This prefix distinguishes all IPv6 addresses of the link-local type.
Some important notes on the characteristics of IPv6 addresses
We summarize below some important aspects of IPv6, the version of the Internet Protocol which effectively allows you to eliminate the NAT in contexts where this is useful and to add greater attention to the correct design and routing of the subnet.
IPv6 addresses are 128 bits long and written as 8 four-letter hexadecimal blocks separated by colons (example 2001:db8:3333:4444:5555:6666:7777:8888 ).
In IPv6 addresses leading zeros may be omitted and groups of zeros may be omitted by using two “colons” in succession, but only once in an address so as not to create ambiguity. For example 2001:4860:4860::8888 is one of the IPv6 addresses used by Google DNS servers .
Network prefixes are virtually always 64-bit long, with a 64-bit client suffix, using CIDR notation .
All addresses must be treated as if they are globally unique, even if they are located only within the enterprise network.
There is no need to assign addresses centrally via DHCP , as nodes can now assign themselves addresses in the vast local 64-bit client space.
Since data packets are globally and uniquely routable, there is also no need, as mentioned, for NAT and port forwarding .
The fact that IPv6 overcomes NAT should not be considered as a security problem : the protection, including that of any public IPv6 addresses used by devices connected downstream, is provided by the firewall of the router and certainly not by the use of NAT.
What real benefits does IPv6 bring to a business, office or home network
The theory is clear, but speaking of real advantages, what are the benefits that the use of IPv6 delivers to business users, professionals and individuals?
– Assume you are behind the NAT set up by your telecom operator on IPv4 connectivity . Well, IPv6 traffic is still globally routable in this case and can be managed, for example, to receive incoming connection requests. While using a network nattata on IPv4 you can for example activate with IPv6, very simply, a VPN server or a game server.
With IPv6 it is even possible to host a server and expose it on the Internet by creating a hotspot on the mobile network !
– IPSec VPNs are widely used but often don’t work well due to NAT. This is no longer a problem with IPv6.
– In case you provide services, it is no longer necessary to use different ports or the reverse proxy mechanism to separate the traffic on the WAN port .
– The availability of link-local addressing over IPv6 means that it is no longer necessary to assign addresses on point-to-point links or on isolated networks.
The transition mechanisms towards IPv6
The strong imbalance that still remains today in favor of the use of IPv4-based networks requires that operators use tools aimed at making IPv4 and IPv6 coexist.
In most cases, dual-stack networks are used , a reference solution that has been supported for years. With this configuration, both IPv4 and IPv6 are supported across the entire network, and resources are accessible through one or the other version of the Internet Protocol .
All network segments must be assigned an IPv4 and IPv6 subnet, and all routers must have routing tables for both IPv4 and IPv6.
In some cases, recourse is made on the telecommunications operator side to solutions which envisage the encapsulation of IPv6 traffic within IPv4 such as 6rd or IPv6 Rapid Deployment .
As we have already highlighted, many providers do not have the availability of large IPv4 blocks so they have decided to implementIPv6-only networks obviously allowing IPv4 traffic in parallel as well. In these cases, however, the same IPv4 address is shared among multiple subscribers using CGNAT and MAP-T technologies .
