Even though I have been around computers for almost three (3) decades - I have completely given up on IPv6 - my old brain cannot grasp the logic - and I am sure there is some buried somewhere.
Why is it that my uex.dk mirror is not affected by this? My rsync service lives happily with the IPv4 address.
It must be related to the it-departments of the majority of the mirror providers are not aware of the issue or more like not aware that they have a huge problem with their IPv6 assignment - if they have any at all - maybe I am just the lucky guy where my ISP does not implement IPv6 for their customers - but I really don’t know. By the way I have not created any AAAA record - I cannot see what difference it makes - I get it - a lot of infrastructure with more and more IOT devices - like cameras etc - but I do fail to see why IPv6 should be necessary for every small network on the globe.
But those IOT devices should really run on private networks - not public - and as such you can build some really huge networks using the 10.x.x.x network address space but for any normal household a 192.168.x.y/24 will suffice.
I am recommending that @philm takes down the IPv6 addresses as it solves very little and is creating sync issues for almost the entire mirror infrastructure.