Comment by apatheticonion
7 days ago
Does IPV6 change this dynamic at all?
It's conceivable that a VPN provider could change the V6 IP on their server every hour for the rest of time and still get unique addresses.
If the VPN server only has an IPV6 address and no V4 address, can they connect to the target website?
IP addresses are routed in aggregate groups using BGP. The groups are called Autonomous Systems and are handed out to ISPs. Your home ISP has a bunch. The ISP that hosts your virtual server has some too. You can see the one you’re connecting from right now with tools like https://bgp.tools and https://bgp.he.net.
The number of these systems scales in a reasonably tractable way — on the order of the number of ISPs and physical Internet infrastructure around which traffic needs to be routed.
As well as making aggregate routing possible you can use the ISP’s registration details see what location (or legal jurisdiction) a whole chunk of address space has. Hopping around IP addresses will give you unique ones every five minutes but they’ll all still be inside 2001:123::/32 from AS1234 aka Apathetic Onion’s Finest Habidashery and Internet Connections LLC, Delaware, USA.