Basically what the title says. Here’s the thing: address exhaustion is a solved problem. NAT already took care of this via RFC 1631. While initially presented as a temporary fix, anyone who thinks it’s going anywhere at this point is simply wrong. Something might replace IPv4 as the default at some point, but it’s not going to be IPv6.
And then there are the downsides of IPv6:
- Not all legacy equipment likes IPv6. Yes, there’s a lot of it out there.
- “Nobody” remembers an IPv6 address. I know my IPv4 address, and I’m sure many others do too. Do you know your IPv6 address, though?
- Everything already supports IPv4
- For IPv6 to fully replace IPv4, practically everything needs to move over. De facto standards don’t change very easily. There’s a reason why QWERTY keyboards, ASCII character tables, and E-mail are still around, despite alternatives technically being “better”.
- Dealing with dual network stacks in the interim is annoying.
Sure, IPv6 is nice and all. But as an addition rather than as a replacement. I’ve disabled it by default for the past 10 years, as it tends to clutter up my ifconfig overview, and I’ve had no ill effects.
Source: Network engineer.
I’d be somewhat lenient when it comes to IPv6 if it used 64 bit addresses instead of 128bit. It would still not be needed thanks to NAT, CIDR and DHCP, but at least a 64bit address space is more manageable.
It’s great for backbone and public address space - and maybe in enterprise, but there it’s a costly transition that won’t happen immediately. Things will change as hardware ages out and is replaced.
New infrastructure will be mostly IP6.
And when people leave the office, their machines will connect to, and transit IP4 networks, so they’ll still need to address how everything works over IP4 (say VPN connections, any hardware/software that’s still IP4 dependent in the data centers, etc).