People who keep thinking this is a technical problem that can be engineered away are confused. People who think the relative cost of doing lookup for IPV4/IPV6 is visible to TCO are confused. Just because you can observe technical differences doesn't mean they are important, it may mean you're being affected by availability heuristics bias, you think that the things you understand must contain the solution to the problem. IPv6 problem is, very few companies in developed markets need it to do business, as customers are just bouncing between established players, no new organic growth. Those companies choosing to do it increase their cost for no utility, so it is an objectively bad decision for many to do IPv6. People who have sentimental attachment to versions of IP protocols are a minority, most just want that customers continue paying their invoices and keep accepting the product. It is almost guaranteed we are married to IPv4 past our life cycles, because there will be a lot of drivers to keep it. Even though dual-stack increases cost for our vendors and us, each of us can transfer the cost to our customers with margins, fixing it would mean less revenue. Like infosec, it'll want things to remain relatively broken, as everyone in position to change it are capitalising on keeping it. -- ++ytti