> There's a surprising number of people who think you could magically expand the IPv4 address space in a backwards compatible manner. There is a (somewhat) bac

> There's a surprising number of people who think you could magically expand the IPv4 address space in a backwards compatible manner. There is a (somewhat) backward-compatible way to do this at least for TCP and UDP: Instead of assigning an IPv4 network prefix (or one single IP address as a special case), assign a tuple (IPv4 network prefix, port prefix), i.e. by firewall rules not every source port can be used from every IP address for TCP and UDP connections. Is this a better solution than IPv6? I clearly don't think so. But it is an ugly, hacky solution that is theoretically possible if one really insists that one wants to keep using IPv4 (only), and needs to magically expand the address space.