anchor.diff:      % Handle errors returned during initial parsing of a request. These errors
       % occur before the transaction layer is notified of the requests, so there
       % are never any server transactions to handle the errors. Just send them.
  -    transportlayer:send_result(Header, Socket, "", Status, Reason, ExtraHeaders).
  +    {_, Method} = sipheader:cseq(keylist:fetch("CSeq", Header)),
  +    case Method of
  +	"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.
   
   process_parsed_packet(Socket, {request, Method, URI, Header, Body}, Origin) ->
       NewHeader1 = fix_topvia_received(Header, Origin),
  
positive.code: 
  check_packet({request, Method, URI, Header, Body}, Origin) ->
      check_supported_uri_scheme(URI, Header),
      {_, FromURI} = sipheader:from(keylist:fetch("From", Header)),
      sanity_check_uri("From:", FromURI, Header),
      {_, ToURI} = sipheader:to(keylist:fetch("To", Header)),
      sanity_check_uri("To:", ToURI, Header),
      case sipheader:cseq(keylist:fetch("CSeq", Header)) of
  	{unparseable, CSeqStr} ->
  	    logger:log(error, "INVALID CSeq ~p in packet from ~s", [CSeqStr, origin2str(Origin, "unknown")]),
  
negative.code:     end.
  
  send_result(Request, Socket, Status, Reason, ExtraHeaders) ->
      {Method, URI, _, _} = Request,
      case Method of
  	"ACK" ->
  	    logger:log(normal, "Sipserver: Suppressing application error response ~p ~s in response to ACK ~s",
  			[Status, Reason, sipurl:print(URI)]);
  	_ ->
  	    case transactionlayer:send_response_request(Request, Status, Reason, ExtraHeaders) of
  		ok -> ok;	
  		_ ->
  		    {Method, URI, Header, Body} = Request,
  		    logger:log(error, "Sipserver: Failed sending caught error ~p ~s (in response to ~s ~s) " ++
  	    			"using transaction layer - sending directly on the socket we received the request on",
  	    			[Status, Reason, Method, sipurl:print(URI)]),
  		    transportlayer:send_result(Header, Socket, "", Status, Reason, ExtraHeaders)
  	    end
      end.
  
  internal_error(Request, Socket) ->
  