diff --git a/pkgs/build-support/fetchurl/mirrors.nix b/pkgs/build-support/fetchurl/mirrors.nix
index c6c294d5504..c4841c50d94 100644
--- a/pkgs/build-support/fetchurl/mirrors.nix
+++ b/pkgs/build-support/fetchurl/mirrors.nix
@@ -159,7 +159,7 @@ rec {
 
   # Debian.
   debian = [
-    #ftp://ftp.au.debian.org/debian/
+    ftp://ftp.au.debian.org/debian/
     ftp://ftp.de.debian.org/debian/
     ftp://ftp.es.debian.org/debian/
     ftp://ftp.fr.debian.org/debian/