[amluto]

Why do I need private addresses?

Okay, in real life I need private addresses because I connect to things that are only available over IPv4. So there’s some negotiation to make sure that my private network does not have an addressing conflict with the other network, there are NATs in the way, and traceroute gives output that is every bit as bad as you would expect. The ACLs that everyone (arguably quite reasonably) sets up suck are fiddly because the clients don’t have well defined address ranges. When people allocate /24 subsets out of IPv4 private space, the probability of collision is annoyingly high. Amateur hour indeed.

I would take globally unique but “private” IPv6 addresses, over private links, with private routes (dynamic or static), and ACLs that actually make sense any day. Heck, I would happily go IPv6 only!