IPv6 Explained can it replace IPv4?
IPv6 has been designed to resolve the limitation of the IPv4 design.
IPv4 is designed with a 32 bit address that is limited to power of 32 different addresses which result in little over 4 billions 4,294,967,296 IP addresses to be more precise.
But how can there be more than 4 billion devices connected to the internet today?
IPv6 is getting old
IPv6 first introduced in the 90ties already is older than 21 years.
Every cell phone, smart thermostat, laptop, servers, routers, firewalls. Why have we not run out of IP addresses yet?
It has been resolved in most cases with NAT.
NAT allows for 1 IP address to be public but can easily have 100s of local IP addresses locally.
A real example could be an office building with 2000 systems but to the internet they only have 1 Public IP address.
IPv4 Vulnerable to remote security vulnerabilities
Scan your public IPv4 IP address with the Cloud SaaS Vulnerability Scanner
A NAT allows to forward ports traffic from a public IPv4 address to local IP addresses.
With NAT in mind it is not 32 bits in length but really 48.
Instead this way there is 281,474,976,710,656 281 trillion plus change devices that can be online.
In early stages of NAT a lot of software could not work with it and would break sessions for keep alive.
This caused battery increase on mobile devices.
since NAT doesn't know if a session is alive.
This has been resolved in most modern software with workarounds.
The problem with IPv6 is that it was set out to work as a new network with no backward compatibility to IPv4.
IPv6 has not caught on in popularity yet.
For IPv6 devices to be integrated they must have IPv4 support as well.
Today most devices have dual stack supporting both IPv4 and IPv6.
Another key problem is you need a new DNS infrastructure to support IPv6.
This can force browsers to look both for IPv6 and IPv4 servers which will slow down the experience for the user.
The big advantage with IPv6 is to get rid of NAT and have each device direct on the internet to increase performance.
Another problem is that addresses on IPv4 is easy to remember compared to IPv6 addresses.
Example if you need to write an IP address down it can be difficult with an IPv6 address.
Example of an IPv4 address could be 192.168.1.1
Example of an IPv6 address could be 2001:0db8:85a3:0000:0000:8a2e:0370:7334
Google claim that as of January 2018 22% percent of their traffic is coming over IPv6.
And it is a big rise from 1% in 2013.
Now if looking at other statistics from AMS https://ams-ix.net/technical/statistics/sflow-stats/ipv6-traffic
a much lower rate of IPv6 adoption can be found as low as 2% of all traffic.
Based on real life adoption it might take many years before IPv6 gets more adoption or perhaps it will be replaced by something better? IPv7?