download
https://archive.kernel.org/centos-vault/
https://vault.centos.org/
Choose the corresponding version
Version difference
CentOS-6.9-x86_64-LiveDVD.iso CD running version (desktop version)
CentOS-6.9-x86_64-bin-DVD1.iso normal installation version first copy zhi
CentOS-6.9-x86_64-bin-DVD2.iso normal installation version first Two
CentOS-6.9-x86_64-minimal.iso minimal installation version, dao only the necessary software package
CentOS-6.9-x86_64-netinstall.iso network installation version, used to install through the network after startup