In order to conserve the limited bandwidth available, ISO images are not downloadable from mirror.centos.org

http://mirror.shastacoe.net/centos/8.3.2011/isos/x86_64/
http://packages.oit.ncsu.edu/centos/8.3.2011/isos/x86_64/
http://mirror.metrocast.net/centos/8.3.2011/isos/x86_64/
http://mirrors.xmission.com/centos/8.3.2011/isos/x86_64/
http://mirror.ette.biz/centos/8.3.2011/isos/x86_64/
http://mirror.compevo.com/centos/8.3.2011/isos/x86_64/
http://mirror.es.its.nyu.edu/centos/8.3.2011/isos/x86_64/
http://centos.mirrors.hoobly.com/8.3.2011/isos/x86_64/
http://mirrors.tripadvisor.com/centos/8.3.2011/isos/x86_64/
http://mirror.pit.teraswitch.com/centos/8.3.2011/isos/x86_64/
http://mirrors.tummy.com/mirrors/CentOS/8.3.2011/isos/x86_64/
http://mirror.cs.vt.edu/pub/CentOS/8.3.2011/isos/x86_64/
http://mirror.sesp.northwestern.edu/centos/8.3.2011/isos/x86_64/
http://mirror.jaleco.com/centos/8.3.2011/isos/x86_64/
http://mirror.hostduplex.com/centos/8.3.2011/isos/x86_64/
http://centos.host-engine.com/8.3.2011/isos/x86_64/
http://mirror.mia11.us.leaseweb.net/centos/8.3.2011/isos/x86_64/
http://centos.den.host-engine.com/8.3.2011/isos/x86_64/
http://mirror.steadfastnet.com/centos/8.3.2011/isos/x86_64/
http://mirrors.sonic.net/centos/8.3.2011/isos/x86_64/
http://mirror.sfo12.us.leaseweb.net/centos/8.3.2011/isos/x86_64/
http://mirrors.mit.edu/centos/8.3.2011/isos/x86_64/
http://mirrors.maine.edu/CentOS/8.3.2011/isos/x86_64/
http://mirrors.cmich.edu/centos/8.3.2011/isos/x86_64/
http://linux.cc.lehigh.edu/centos/8.3.2011/isos/x86_64/
http://mirror.twinlakes.net/centos/8.3.2011/isos/x86_64/
http://repo1.dal.innoscale.net/centos/8.3.2011/isos/x86_64/
http://mirror.teklinks.com/centos/8.3.2011/isos/x86_64/
http://mirror.cogentco.com/pub/linux/centos/8.3.2011/isos/x86_64/
http://bay.uchicago.edu/centos/8.3.2011/isos/x86_64/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/

Mirrors verified Tue Jan 19 22:25:44 2021 UTC

You can also download the ISO images using bittorrent, a peer-to-peer file sharing protocol. The .torrent files can be found from CentOS mirrors. Various bittorrent clients are available, including (in no particular order of preference): utorrent, vuze (Azureus), BitTorrent, Deluge, ctorrent, ktorrent, rtorrent and transmission. Packaged copies of various torrent clients for CentOS can be found in the repositories listed in the following wiki article: https://wiki.centos.org/AdditionalResources/Repositories