anchor.diff:  		    throw({sipparseerror, request, Header, 400, "CSeq Method " ++ CSeqMethod ++
   			   " does not match request Method " ++ Method});
   		true -> true
  -	    end;
  -	_ ->
  -	    logger:log(error, "INVALID CSeq in packet from ~s", [origin2str(Origin)]),
  -	    throw({sipparseerror, request, Header, 400, "Invalid CSeq"})
  +	    end
       end,
       case yxa_config:get_env(detect_loops) of
   	{ok, true} ->
  
positive.code: 	    %%   retransmissions or disallowed responses (such as a response to ACK).'
  	    logger:log(normal, "Sipserver: Suppressing parsing error response ~p ~s because CSeq method is ACK",
  		       [Status, Reason]);
  	_ ->
  	    transportlayer:send_result(Header, Socket, <<>>, Status, Reason, ExtraHeaders)
      end,
      ok.
  
negative.code: %% Returns : ok
  %%--------------------------------------------------------------------
  parse_do_internal_error(Header, Socket, Status, Reason, ExtraHeaders) ->
      case sipheader:cseq(Header) of
  	{unparseable, CSeqStr} ->
  	    logger:log(error, "Sipserver: Malformed CSeq (~p) in response we were going to send, dropping response",
  		       [CSeqStr]);
  	{_Num, "ACK"} ->
  	    %% Empirical evidence says that it is a really bad idea to send responses to ACK
  	    %% (since the response may trigger yet another ACK). Although not very clearly,
  	    %% RFC3261 section 17 (Transactions) do say that responses to ACK is not permitted :
  