anchor.diff:  , iptables
   }:
   
  +let
  +  version = "4.6.0";
  +  tarballUrls = [
  +    "mirror://kernel/linux/utils/net/iproute2/iproute2-${version}.tar"
  +  ];
  +in
   stdenv.mkDerivation rec {
  -  name = "iproute2-4.5.0";
  +  name = "iproute2-${version}";
   
     src = fetchurl {
  -    url = "mirror://kernel/linux/utils/net/iproute2/${name}.tar.xz";
  -    sha256 = "0jj9phsi8m2sbnz7bbh9cf9vckm67hs62ab5srdwnrg4acpjj59z";
  +    urls = map (n: "${n}.xz") tarballUrls;
  +    allowHashOutput = false;
  +    sha256 = "74fc6a8ad085be095a159f8158bbaf385b42af9e101619f233f1ae466829d406";
     };
   
     nativeBuildInputs = [
  
positive.code:       "DOCDIR=$TMPDIR"
      )
    '';
  
    meta = with stdenv.lib; {
      homepage = http://www.linuxfoundation.org/collaborate/workgroups/networking/iproute2;
  
negative.code:   preBuild = ''
      makeFlagsArray+=(
        "DESTDIR="
        "PREFIX=$out"
        "SBINDIR=$out/bin"
      )
      buildFlagsArray+=(
        "CONFDIR=/etc/iproute"
  