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You wouldn't route traffic over the NAT using ULA to the outside world. You'd use GUA space for that. Collisions between two private networks is very low was m
by ArchOversight 4y ago
You wouldn't route traffic over the NAT using ULA to the outside world. You'd use GUA space for that.
Collisions between two private networks is very low was my primary point, and thus NAT is not a thing that needs to exist.
- greyface- 4y agoYes, exactly. And if you have two upstreams, there's no single GUA prefix that makes sense to use in all situations. You make your routing decision, then you NAT (er, sorry, NPTv6, which is Totally Not The Same Thing As NAT) to the GUA prefix corresponding with the network that you're egressing from. If you don't need Internet connectivity, yes, NAT-free ULAs work fine.
- akira2501 4y agoNAT requires kernel connection tracking. NPT explicitly does not. There's a lot of useful implications to this.
- greyface- 4y agoStateful NAT requires kernel connection tracking. Stateless NAT does not, and is still a form of NAT. It's sometimes used in IPv4 networks, even!
- akira2501 4y agoDidn't you mean stateful NAT when you were making the comparison?
- greyface- 4y agoThat wasn't my intent, but I see how it reads that way now. The parenthetical was me griping about naming, not meant to update the meaning of the sentence. In the dual-upstream scenario, I'd use stateless NAT with a single on-link prefix (GUA or ULA).