deb http://deb.debian.org/debian stretch main
deb-src http://deb.debian.org/debian stretch main

deb http://deb.debian.org/debian-security/ stretch/updates main
deb-src http://deb.debian.org/debian-security/ stretch/updates main

deb http://deb.debian.org/debian stretch-updates main
deb-src http://deb.debian.org/debian stretch-updates main

deb http://deb.debian.org/debian stretch-backports main contrib non-free
deb-src http://deb.debian.org/debian stretch-backports main contrib non-free