> Is the general model of public/private subnet still valid? Or are you saying in a ipv6-only world, there's no need for separate subnets? This is one thing th

> Is the general model of public/private subnet still valid? Or are you saying in a ipv6-only world, there's no need for separate subnets? This is one thing that's actually been vastly improved in IPv6 (IMO), though I guess it is somewhat more complicated, it is standardized. In the IPv4 model, your hosts get 'internal' addresses and some gateway device translates these addresses to/from the associated 'public' addresses as necessary. Behaviour when multiple addresses are assigned is undefined, and there are plenty of weird corner cases with internal hosts trying to hit the public addresses of forwarded services and such. In the typical IPv6 model, your hosts (if they need to talk to the Internet) get a (or several) Globally Unique Address (GUA), which is routeable on the Internet. Optionally, hosts can also have a Unique Local Address (ULA) which is analogous to an RFC1918 address in IPv4. Because it's codified in the standard, hosts will choose the correct source address depending on the destination they want to talk to; a ULA address if the server is also ULA, and a GUA source will be chosen for talking to GUA addresses. In a typical corporate network, you'd give hosts both classes of address, and your internal services run on ULA addressing. But in most residential or hosting environments, you'd just use GUA as there is no benefit to segregating things this way.