On Thu, 18 Nov 2021 at 15:04, Leo Vegoda <[email protected]> wrote: > On Thu, Nov 18, 2021 at 6:05 AM Tim Chown <[email protected]> wrote: > > Personally, I’d say just get on with IPv6. > This gets my vote. >
So... This is tricky. IPv4 isn't going away for residential and most SME connectivity -- it's just too difficult to live without, and too entrenched in the psyche of the IT tech support PFY. You still have all the same IPv4 addressing problems, you've just shifted a portion (bulk, even) of the traffic onto IPv6. IPv4 CGNAT at large scale is getting ridiculously cheap to do, so it's incredibly unlikely that any "big" ISP is going to offer an IPv6-only connection, because a large number of people expect to be able to login to their router, assign static IPs to their CCTV cameras, run a NAS at home, tinker with a raspberry pi, that kind of thing -- not to mention at least one of the new mass-market games consoles working with IPv6, but not working if there is *only* IPv6. >From what I'm reading, using mdns to "solve" the "how do I login to my router" issue doesn't work out of the box when you only have link-local addressing, which you have because you're logging into your router because the "internet is down", and you can't just use the gateway IP because no RA has been issued yet! How lucky we are with RFC1918 addressing and the ability to NAT44 to whatever the outside IP address is today, especially when random crash-reboots of the CPE leads to new IPv6 prefixes every time causing blackholing of IPv6 traffic if the old RA hasn't been expired! IPv6 isn't getting rid of the IPv4 addressing problem. To turn off IPv4 would be commercial suicide considering how little effort is required to continue running IPv4, the ISP would get branded as "incompatible with some of my devices and I bet they are with yours too" with IPv4 connectivity being then offered as a value proposition and differentiator, a result none of us want to see! Sure, it's advisable to run IPv6 in your networks now, but we just aren't going to see IPv4 go significantly away in terms of addressable hosts anytime soon. Right now, IPv6 feels like this monumental waste of time to be advocating for with such gusto because it doesn't solve the IPv4 addressing issue for these issues. Those that are able to move to IPv6 on the content side will do so, but likely not until they feel the need to, and they're always going to need IPv4 support somehow, likely via L7 proxy. For the eyeball ISPs especially, MAP-T etc can make stateless NAT possible that will massively extend the utility of IPv4, just like NAT overloading did 20 years ago, and as a by-product help bring them into compliance with various laws regarding knowing which subscriber had which IP/Port tuple at a particular time without horrendous amount of logging. If (eyeball) ISPs want to lower their costs of things like CGNAT boxes, then sure, IPv6 is going to help there by moving some of the traffic, but at no point are we "solving the IPv4 problem" because you aren't moving all of the traffic, so you still need IPv4 somewhere within an endpoint network, so you still need IPv4 almost everywhere within the ISP network. Trust me, I wish it was different, but I can not see how there would be any less than 95%+ of residential or enterprise/SME networks with IPv4 enabled. Mobile is different, and almost a solved problem. Content serving is a little trickier than that (you need an L7 proxy or similar) but still relatively easy to go IPv6-only. That LAN at home or the office with less than 100 people? Yeah, that's not changing anytime soon for the vast majority of people out there... There is just no benefit to turning IPv4 off for them, and lots of downsides. In fact, I have first-hand experience of being verbally chastised in a public forum for "not having IPv6 turned on by default" -- when it was precisely not enabled by default because it broke too often, it wasn't through laziness! I can (privately) point to several organisations that have received so much flak for not having IPv6 that the mere sight of the term causes a canned "we're working on it" and disregarding the message as angsty nerds. I'd be delighted if someone could now prove me wrong or at least show me where I've missed something vital -- but all too often this argument descends into ideological puritanism and zealotry, so please constrain answers to eyeball ISP connections to the layperson's home or SOHO. M
