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