deb http://cdn.debian.net/debian/ stable main contrib non-free
# deb-src http://cdn.debian.net/debian/ stable main contrib non-free
+# security updates:
+ deb http://security.debian.org/ stable/updates main contrib
+# deb-src http://security.debian.org/ stable/updates main contrib
+
# official debian repository:
# deb http://ftp.debian.org/debian/ stable main contrib non-free
# deb-src http://ftp.debian.org/debian/ stable main contrib non-free