I know that a VPN may be used in lots of different ways for lots of different things, so I'm not suggesting that IPv6 removes the need for a VPN completely. I'm interested in one particular use-case:
I have a cellular (GSM) router, and traditionally, a standard SIM from my local network operator will give me a dynamic IPv4 address. In order to be able to reach my router from the internet, today I use a VPN. This does 2 things:
- It gives my router a static IPv4 address. This will not change, if the dynamic IPv4 address assigned by the operator changes, or if I change operators.
- It allows me to traverse the operator's NAT firewall. If my router is acting as a server, I can initiate a connection to it.
I'm still learning about IPv6, but it seems to me that if a network operator supports IPv6 (say Verizon Wireless in the US), then I no longer need a VPN:
- 3GPP cellular operators use SLAAC, and I get a Global Unicast Address. This, by definition, is globally-routable. There is no NAT.
- I know what /64 prefix the operator assigns, and I know what Interface ID will be used (either EUI-64 or RFC 7217), so I have a static IPv6 address.
Is this correct? Or am I missing something?
Of course, I'm aware that a VPN provides extra security, because it adds authentication and encryption. But lets assume for the purposes of this discussion that I will use an IPv6 firewall, or IPsec, or TLS at the application layer, for security.
I know I could continue to use a VPN with IPv6, and this would allow me to use Unique Local IPv6 Addresses just like my old private IPv4 addresses. But why would I need to?