> After that, it becomes time for the would-be abbreviators to appear and tell me that the address for this computer is wrong, somehow, as if I ever had an active part in selecting the address to begin with
Ok, I'll bite. Why exactly do you not have the ability to select the address?
As a general rule, if you care about an IPv6 address enough that you have to type it in somewhere, you should be assigning it manually, and if you're doing that you can make it a lot friendlier than 2601:3c7:4f80:1a01:4d2:3b7a:9c10:6f5e. The whole second half of the address can be shortened to ::<digit>, where the length of <digit> scales logarithmically to the number of memorable addresses you want in that network.
My network at home uses ULA addresses for everything, and I just use my phone number in the first half, so the address of my router at home is e.g. fd21:2555:1212::1, my NAS is fd21:2555:1212::a, etc. The global (GUA) address is something like 2601:abc:def:1201::a, which isn't that bad.
Hell, if you don't care about the potential of conflicts if you ever merge networks with someone else, you can just use fd00:: as your ULA prefix, and your router can be fd00::1, your NAS box can be fd00::2, etc. Shorter than IPv4 addresses!
> Ok, I'll bite. Why exactly do you not have the ability to select the address?
I never said I don't have the ability. I may; I may not. I myself don't know that one way or the other. It's big ball of mystery to me.
What I did say was I didn't have a hand in that long address; ie, I was not involved in making it that way. I don't know by what mechanism (if any) the long address came to be. I don't know if it was assigned, or selected, or a product of /dev/random, or if it was a combination of these things.
I only know that I didn't choose it, and that the way that it is simply sucks.
> As a general rule, if you care about an IPv6 address enough that you have to type it in somewhere, you should be assigning it manually
Perhaps. But that's a twist that we didn't have with the defacto norm that we landed on in IPV4 world some decades ago, wherein: A LAN address was dynamic by default, assigned via a local DHCP server, and presented as a dotted octet. The WAN address was also dynamic, and assigned by someone else's DHCP server, and presented as a dotted octet. The two addresses were never related to eachother.
And in that world: If I wanted to run a local service for someone else (on the internet) to use right now -- today (maybe not tomorrow or next week, but definitely right now), then all I needed to relay to them was the simple dotted octet that identified my WAN interface.
That part was easy with IPV4.
> and if you're doing that you can make it a lot friendlier than 2601:3c7:4f80:1a01:4d2:3b7a:9c10:6f5e. The whole second half of the address can be shortened to ::<digit>, where the length of <digit> scales logarithmically to the number of memorable addresses you want in that network.
Maybe my occipital lobe is just broken somehow, but it's hard to look at an address like that and quickly discern where the second half of that address even begins. Why am I looking for a half of it, anyway? (From whence is that "half" delineation deduced?)
But, sure. Half of it, for whatever reason that it is half. So 2001:3c7:4f80:1a01::3 can be one system on the LAN and 2001:3c7:4f80:1a01::4 can be another? And these are complete, unique, world-routable addresses that someone else on the world can connect to with the appropriate firewall rules in-place?
But the first half is assigned by my ISP and changed at their whim, right? I can't reliably connect from 2001:3c7:4f80:1a01::3 to 2001:3c7:4f80:1a01::4 even if those two computers are right next to eachother on my LAN because tomorrow, the first "half" might change -- correct?
I don't like the idea of my LAN's addressing being dictated by whatever ISP I'm using at the moment. (Spectrum is down, switch to hotspot as backup, and oh lol: the LAN is all different now. IPV4, as-implemented, never did that to me.)
> Hell, if you don't care about the potential of conflicts if you ever merge networks with someone else, you can just use fd00:: as your ULA prefix, and your router can be fd00::1, your NAS box can be fd00::2, etc. Shorter than IPv4 addresses!
I don't even know what ULA means.
But it sounds like ULA means something like RFC 1819 10.x.x.x private addresses, wherein: A person can do whatever they want, and it never touches the Internet so it's fine.
That sounds great, in concept. But now we're back to using private, non-routable addresses? Isn't that the same thing we were seeking to avoid?
How does fd00::3 then communicate with the greater internet? NAT?
edit: And then, how is fd00::3 superior to 10.3 [10.0.0.3] on the LAN?
> then all I needed to relay to them was the simple dotted octet that identified my WAN interface.
Then either you must be one of the precious few people who owns a /24 or something for their house and gives each device a global IPv4 address, or you’re forgetting the part where you have to go to your router and pick a random port to forward, and open it up. Otherwise you don’t just “have” an independent WAN address on each host in your network, like you do with a typical IPv6 setup.
> So 2001:3c7:4f80:1a01::3 can be one system on the LAN and 2001:3c7:4f80:1a01::4? And these are complete, unique, world-routable addresses that someone else on the world can connect to with the appropriate firewall rules in-place?
yes
> But the first half is assigned by my ISP and changed at their whim, right?
like your IPv4 WAN address does, yes
(About ULA)> That sounds great, in concept. But now we're back to using private, non-routable addresses?
like IPv4 yes. But in IPv6 you can have both, a ULA (like rfc1918 addresses) and a GUA (an actual routable address) on the same subnet. It’s fine. Use the ULA for your LAN use cases where you need to use a LAN IP address (bonus, it stays the same even if your ISP changes your prefix) and use the GUA for the rare occasion where you need someone on the other side of the world to talk to one of your hosts. You’re gonna have to poke a firewall rule anyway, so you just pick a decent GUA address while you’re at it ($global_prefix::1, etc.) You can do whatever you want, it’s your prefix (until your ISP changes it.)
> How does fd00::3 then communicate with the greater internet? NAT?
no need, it just has another address for global traffic. Typically one of the really long random ones, that’s what they’re for. (They even change for every external service you talk to.). The whole purpose of the long impenetrable fully-populated 128-bit address, is basically only necessary for privacy (I.e. you intentionally want the address to be meaningless.) For anything where you’re persisting an IP somewhere, just pick a better address for it. $prefix::1, whatever. It’s a single ifconfig command even on macOS, ditto Linux. (Windows I have no experience with but I’m sure that too.) Trivial to persist across reboots, etc.
The ISP changing the prefix is a real problem though, and is far too difficult to rely on persisted global addresses for that reason. Using a ULA anywhere you need to configure an IP address locally is the only sane option, and for global addresses it’s simply a huge pain in the ass if you ever get a different prefix.
> edit: And then, how is fd00::3 superior to 10.3 [10.0.0.3] on the LAN?