The reason IPv6 was originally added to the DOCSIS specs, over 20 years ago, is because Comcast literally exhausted all RFC1918 addresses on their modem management networks.
My favourite feature of IPv6 is networks, and hosts therein, can have multiple prefixes and addresses as a core function. I use it to expose local functions on only ULA addresses, but provide locked down public access when and where needed. Access separation is handled at the IP stack, with IPv4 it’s expected to be handled by a firewall or equivalent.
many “unused” IP addresses are unused because they’re kinda like having spare parts: if you’re planning on extending your network in the futures, your IP block kinda should reflect your end state (ie the parts you need over time to replace or “build” new hosts)
or for blue/green deployments where it’s likely that at least half the IP range will be used in terms of process, but unused most of the time in terms of reachability
and then there’s weird things with splitting up IP blocks into subnets with a division of 3 (the minimum needed for dealing with net splits etc) - eg across availability zones… there are always “waste” IPs because you can’t divide multiples of 8 cleaning into 3
My favorite feature of IPv6 is that there are so many addresses available. Every single IPv4 address right now could have its own entire IPv4 range of addresses in IPv6. It’s mind-boggling huge.
After looking up some numbers, I note we could give every single square MILLIMETER on the planet its own entire IPv4 address space.
…And then every one of those IPv4 addresses could have its own entire copy of the IPv4 address space!
…And that would just be a drop in the bucket compared with IPv6! One good comparison I’ve seen is that you could assign an address to every atom on the surface of the earth (but not inside it) and have enough left over for 100+ more earths.
Rough math for the square millimeters:
The surface area of the earth is roughly 510 trillion square millimeters. Let’s round that up to a quadrillion or 1015.
The number of IPv6 addresses is 2128 or 3.4x1038. To be conservative again, let’s just round that down to 1038.
1038 / 1015 = 1023 IPv6 addresses per square mm of earth.
IPv4 address space is 232 or around 4 billion. let’s round up to 10 billion or 1010.
So then 1023 / 1010 = 1013 IPv6 addresses per IPv4 address per square mm of earth.
1013 / 1010 =
1,000 IPv6 addresses
per IPv4 address
per IPv4 address
per square mm of earth.
And that was with the conservative estimates along the way. I think it would actually be tens of thousands.
The reason IPv6 was originally added to the DOCSIS specs, over 20 years ago, is because Comcast literally exhausted all RFC1918 addresses on their modem management networks.
My favourite feature of IPv6 is networks, and hosts therein, can have multiple prefixes and addresses as a core function. I use it to expose local functions on only ULA addresses, but provide locked down public access when and where needed. Access separation is handled at the IP stack, with IPv4 it’s expected to be handled by a firewall or equivalent.
They kept talking it was because address exaustion, and IANA sold all the remaining blocks they had…
I tested it at the time. Ran nmap ping scan across a block all night with zero results. IANA sold the internet
many “unused” IP addresses are unused because they’re kinda like having spare parts: if you’re planning on extending your network in the futures, your IP block kinda should reflect your end state (ie the parts you need over time to replace or “build” new hosts)
or for blue/green deployments where it’s likely that at least half the IP range will be used in terms of process, but unused most of the time in terms of reachability
and then there’s weird things with splitting up IP blocks into subnets with a division of 3 (the minimum needed for dealing with net splits etc) - eg across availability zones… there are always “waste” IPs because you can’t divide multiples of 8 cleaning into 3
https://map.bgp.tools/
https://xkcd.com/195/
My favorite feature of IPv6 is that there are so many addresses available. Every single IPv4 address right now could have its own entire IPv4 range of addresses in IPv6. It’s mind-boggling huge.
you could assign every square meter of the planet an ip and use it for location, and still have addresses left over
Oh it’s way more than that!
After looking up some numbers, I note we could give every single square MILLIMETER on the planet its own entire IPv4 address space.
…And then every one of those IPv4 addresses could have its own entire copy of the IPv4 address space!
…And that would just be a drop in the bucket compared with IPv6! One good comparison I’ve seen is that you could assign an address to every atom on the surface of the earth (but not inside it) and have enough left over for 100+ more earths.
Rough math for the square millimeters:
The surface area of the earth is roughly 510 trillion square millimeters. Let’s round that up to a quadrillion or 1015.
The number of IPv6 addresses is 2128 or 3.4x1038. To be conservative again, let’s just round that down to 1038.
1038 / 1015 = 1023 IPv6 addresses per square mm of earth.
IPv4 address space is 232 or around 4 billion. let’s round up to 10 billion or 1010.
So then 1023 / 1010 = 1013 IPv6 addresses per IPv4 address per square mm of earth.
1013 / 1010 =
1,000 IPv6 addresses
per IPv4 address
per IPv4 address
per square mm of earth.
And that was with the conservative estimates along the way. I think it would actually be tens of thousands.
square centimeter is the one I heard
I understand some of these words!