The CentOS Project has developed a GeoIP® enabled system for our CentOS-4 yum updates that generates dynamic mirror lists based on two very important items:
1. The connecting location of the client.
2. The current freshness/staleness of the mirrors for that region.
This update system will allow us to read the connecting location of a client, look for fresh mirrors close to that client, and provide a list of ten mirrors for each CentOS repository that is included in the file /etc/yum.repos.d/CentOS-Base.repo. The selection base is currently about 100 mirrors from around the world.