On Mar 30, 2022, at 08:09 , Jared Brown <nanog-isp@mail.com> wrote: Owen DeLong via NANOG wrote:When your ISP starts charging $X/Month for legacy protocol supportOut of interest, how would this come about?ISPs are facing ever growing costs to continue providing IPv4 services.Could you please be more specific about which costs you are referring to?Costs of address acquisition Costs of CGNAT systems in lieu of address acquisition costs Costs of increasing support calls due to IPv4 life support measures in other networks. etc.It's not like IP transit providers care if they deliver IPv4 or IPv6 bits to you.True, but adding customers requires additional addresses at some point. IPv6 addresses are cheap compared to IPv4 addresses. Owen