CDN and mirrors actually corresponds to two different servers, one in The Netherlands and one in USA. There are both accessible through both IPv4 and IPv6. In case you leave far from these countries, you will find below a probably incomplete list of mirrors.

Given the limited number of users for the architectures hosted by debian-ports, a lot more bandwidth is used to synchronise the mirrors than by the end users. We have therefore decided to use a content distribution network (CDN) to distribute the debian-ports archive. It is recommended to use it in priority.

MirrorCountryURLPushIPv6Architectures All (CDN) http Yes Yes All DE http, ftp, rsync Yes No All

Adding new mirrors

You can contact the mirror team in case you are interested in running a mirror for the debian-ports archive.