[pjc50]

> The software above the IP layer is still UDP, TCP, HTTP, SMTP

Yes, almost all of which has to be aware of which address family it's using in order to work.

[stephen_g]

I've been writing all my socket code (this is embedded so plain C) to be automatically compatible with either IPv4 or IPv6 for, what, ten years? I thought everybody did that (it's best practice).

Don't most higher level languages also just do this by default under the hood?