anchor.diff:  %% the common application but diameter doesn't care.
   -define(APP_ID, ?DIAMETER_APP_ID_COMMON).
   
  +%% An Application-ID the server doesn't support.
  +-define(BAD_APP, 42).
  +
   %% Config for diameter:start_service/2.
   -define(SERVICE(Name),
           [{'Origin-Host', Name ++ "." ++ ?REALM},
  
positive.code: 
  dict(['ACR' | _]) ->
      ?ACCT;
  dict(_) ->
      ?BASE.
  
  
negative.code:     #diameter_packet{bin = <<H:8/binary, _ApplId:4/binary, T/binary>>}
          = E
          = diameter_codec:encode(?BASE, Pkt#diameter_packet{msg = Req}),
      E#diameter_packet{bin = <<H/binary, ?BAD_APP:32/integer, T/binary>>};
  
  prepare(Pkt, Caps, send_error_bit) ->
      #diameter_packet{header = Hdr} = Pkt,
  