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.

[–] Bytemeister@lemmy.world 25 points 17 hours ago (1 children)

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.

[–] gnuplusmatt@reddthat.com 14 points 13 hours ago* (last edited 13 hours ago) (2 children)

you could assign every square meter of the planet an ip and use it for location, and still have addresses left over

[–] Zink@programming.dev 8 points 8 hours ago* (last edited 2 hours ago)

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 10^15^.

The number of IPv6 addresses is 2^128^ or 3.4x10^38^. To be conservative again, let’s just round that down to 10^38^.

10^38^ / 10^15^ = 10^23^ IPv6 addresses per square mm of earth.

IPv4 address space is 2^32^ or around 4 billion. let’s round up to 10 billion or 10^10^.

So then 10^23^ / 10^10^ = 10^13^ IPv6 addresses per IPv4 address per square mm of earth.

10^13^ / 10^10^ =

1,000 IPv6 addresses

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.

[–] SpaceCadet@feddit.nl 2 points 6 hours ago* (last edited 6 hours ago)

square centimeter is the one I heard

[–] madcaesar@lemmy.world 13 points 18 hours ago

I understand some of these words!