Sorry if this is silly question but just because I have an ipv6 address doesn't mean anyone else with an ipv6 address can communicate with me, right? Here is my simplified understanding

(You) <-- (lots of stuff) --> my modem <--> my router <--> my phone

So like even if you had my ipv6 address, am I really addressable? Like can you ping my phone? Send me files across the Internet?

Yes, I could ping your phone if there wasn't a firewall blocking it between you and me.

Thank you for answering. I have so many questions but I'll start with this... When I ping an ipv4 address from outside the home, if something responds to the ping it is my modem/router, right? As in even if I had no computers in the house, you couldn't tell the difference when you ping my ipv4 address, right? My Internet service provider owns my IPv4 address, not me, right? What changes with ipv6? The ISP still owns the IP addresses and is free to reassign them wherever? It isn't like a phone number where I own the number and have a right (in the US) to port it?

> When I ping an ipv4 address from outside the home, if something responds to the ping it is my modem/router, right? As in even if I had no computers in the house, you couldn't tell the difference when you ping my ipv4 address, right? My Internet service provider owns my IPv4 address, not me, right?

Right. IPv4 addresses are expensive, so it's uncommon to have more than one at home.

> What changes with ipv6?

Not a lot. You just have many addresses instead of one. If there were no firewall, someone could ping your router or individual devices, as they have different addresses.

> The ISP still owns the IP addresses and is free to reassign them wherever?

Yes.

> It isn't like a phone number where I own the number and have a right (in the US) to port it?

Correct. You would need direct BGP access to use a portable IPv4/IPv6 address. That generally is not available on residential connections.