centos系统官网

https://www.centos.org/download/

redhat系统官网

https://www.redhat.com/zh

ubuntu系统官网

https://ubuntu.com/download/server

windows系统官网

http://www.microsoft.com/zh-cn/default.aspx

solaris下载

https://www.oracle.com/solaris/solaris11/downloads/solaris-downloads.html

除了上述官网下载，国内也有公用的下载地址

http://mirrors.163.com/

https://www.huaweicloud.com/theme/62428-3-H-undefined