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

http://mirror.ash.fastserv.com/centos/8.4.2105/isos/x86_64/
http://mirror.vtti.vt.edu/centos/8.4.2105/isos/x86_64/
http://us.mirror.nsec.pt/centos/8.4.2105/isos/x86_64/
http://mirror.vcu.edu/pub/gnu_linux/centos/8.4.2105/isos/x86_64/
http://mirror.cs.vt.edu/pub/CentOS/8.4.2105/isos/x86_64/
http://mirror.cogentco.com/pub/linux/centos/8.4.2105/isos/x86_64/
http://mirror.centos.iad1.serverforge.org/8.4.2105/isos/x86_64/
http://mirrors.advancedhosters.com/centos/8.4.2105/isos/x86_64/

http://linux-mirrors.fnal.gov/linux/centos/8.4.2105/isos/x86_64/
http://mirror.fileplanet.com/centos/8.4.2105/isos/x86_64/
http://mirror.dal.nexril.net/centos/8.4.2105/isos/x86_64/
http://mirrors.cmich.edu/centos/8.4.2105/isos/x86_64/
http://mirror.den01.meanservers.net/centos/8.4.2105/isos/x86_64/
http://mirrors.ocf.berkeley.edu/centos/8.4.2105/isos/x86_64/
http://repos.dfw.quadranet.com/centos/8.4.2105/isos/x86_64/
http://mirrors.maine.edu/CentOS/8.4.2105/isos/x86_64/
http://repos.mia.quadranet.com/centos/8.4.2105/isos/x86_64/
http://mirror.ancl.hawaii.edu/linux/centos/8.4.2105/isos/x86_64/
http://mirror.wdc1.us.leaseweb.net/centos/8.4.2105/isos/x86_64/
http://centos.mirror.lstn.net/8.4.2105/isos/x86_64/
http://mirror.atlanticmetro.net/centos/8.4.2105/isos/x86_64/
http://mirrors.gigenet.com/centos/8.4.2105/isos/x86_64/
http://mirror.hostduplex.com/centos/8.4.2105/isos/x86_64/
http://mirror.clarkson.edu/centos/8.4.2105/isos/x86_64/
http://centos.mirror.constant.com/8.4.2105/isos/x86_64/
http://mirror.ette.biz/centos/8.4.2105/isos/x86_64/
http://mirror.mojohost.com/centos/8.4.2105/isos/x86_64/
http://mirror.cs.pitt.edu/centos/8.4.2105/isos/x86_64/
http://centos.mirrors.hoobly.com/8.4.2105/isos/x86_64/
http://yum.tamu.edu/centos/8.4.2105/isos/x86_64/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/

Mirrors verified Mon Nov 15 16:39:26 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