deb http://mirrors.aliyun.com/debian/ stretch main non-free contrib deb-src http://mirrors.aliyun.com/debian/ stretch main non-free contrib deb http://mirrors.aliyun.com/debian-security stretch/updates main deb-src http://mirrors.aliyun.com/debian-security stretch/updates main deb http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib deb-src http://mirrors.aliyun.com/debian/ stretch-updates main non-free contrib deb http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib deb-src http://mirrors.aliyun.com/debian/ stretch-backports main non-free contrib