Debian 9 стандартные репозитории
deb http://deb.debian.org/debian/ stretch main contrib non-free
deb-src http://deb.debian.org/debian/ stretch main contrib non-free
deb http://deb.debian.org/debian/ stretch-updates main contrib non-free
deb-src http://deb.debian.org/debian/ stretch-updates main contrib non-free
deb http://security.debian.org/debian-security/ stretch/updates main contrib non-free
deb-src http://security.debian.org/debian-security/ stretch/updates main contrib non-free