Post #2358497

I disagree with the assertion that new applications should avoid IPv4-mapped addresses in general. New applications should be designed with an IPv6-first mentality, by that I mean that one should first decide on what’s a good design if you don’t need to support IPv4 at all. And once you have that design you can decide how to add IPv4 support, and doing so must not compromise the design you want for IPv6. In some situations it will add complexity to listen on two separate sockets. And more complexity increase the risk of bugs including security vulnerabilities. For that reason I think one need to decide on a case-by-case basis what is the best design for a particular application. Mandating a more complex design is not how we get developers to fix the few applications which still lack IPv6 support.