-deb http://httpredir.debian.org/debian {release} main contrib non-free
-deb http://httpredir.debian.org/debian {release}-backports main
-deb http://security.debian.org/debian-security {release}/updates main contrib non-free
+deb {apt_cdn}/debian {release} main contrib non-free
+deb {apt_cdn}/debian {release}-backports main
+deb {apt_cdn}/debian-security {release}/updates main contrib non-free