Forwarding here (but in readable format) what was sent to centos-mirror-announce list (where all public mirrors are normally subscribed), so sending to centos-devel for awareness :
Just this little mail to announce that we have now put in place the same mechanism to only allow registered third-party mirrors to pull/rsync from us. (ticket https://pagure.io/centos-infra/issue/999)
Due to lack of bandwidth/resources and also sponsored nodes disappearing (and so remaining sponsored infra being overloaded with requests), we had to adapt the process to also have ACL in place for CentOS Stream 9 (as it was already documented for years on https://wiki.centos.org/HowTos/CreatePublicMirrors) to only allow ip address[es] (ipv4 and ipv6) from these registered mirrors (https://pagure.io/centos-infra/issues?status=Closed&tags=mirrormanager&a...)
Should you suddenly be blocked (because you are now using a different ip that differs from the one you added in your initial ticket on centos-infra tracker), feel free to create ticket to request the ip to be updated in our ACL.
Kind Regards,