diff --git a/src/TinyMqtt.cpp b/src/TinyMqtt.cpp
index 1f59474..e9d7ca3 100644
--- a/src/TinyMqtt.cpp
+++ b/src/TinyMqtt.cpp
@@ -174,10 +174,10 @@ bool MqttBroker::compareString(
 	return *good==0;
 }
 
-void MqttMessage::getString(char* &buffer, uint16_t& len)
+void MqttMessage::getString(const char* &buff, uint16_t& len)
 {
-	len = (buffer[0]<<8)|(buffer[1]);
-	buffer+=2;
+	len = (buff[0]<<8)|(buff[1]);
+	buff+=2;
 }
 
 void MqttClient::clientAlive(uint32_t more_seconds)
@@ -226,7 +226,7 @@ void MqttClient::processMessage()
 	std::string s;
 	// Serial << "---> INCOMING " << _HEX(message.type()) << ", mem=" << ESP.getFreeHeap() << endl;
   auto header = message.getVHeader();
-  char* payload;
+  const char* payload;
   uint16_t len;
 	bool bclose=true;
 
@@ -420,15 +420,14 @@ void MqttClient::publish(const Topic& topic, MqttMessage& msg)
 
 void MqttMessage::reset()
 {
-	curr=buffer;
-	*curr=0;	// Type Unknown
+	buffer.clear();
 	state=FixedHeader;
 	size=0;
 }
 
 void MqttMessage::incoming(char in_byte)
 {
-	*curr++ = in_byte;
+	buffer += in_byte;
 	switch(state)
 	{
 		case FixedHeader:
@@ -443,7 +442,7 @@ void MqttMessage::incoming(char in_byte)
 			}
 			else if ((in_byte & 0x80) == 0)
 			{
-				vheader = curr;
+				vheader = buffer.length();
 				if (size==0)
 					state = Complete;
 				else
@@ -464,15 +463,14 @@ void MqttMessage::incoming(char in_byte)
 			break;
 		case Complete:
 		default:
-			curr--;
 			Serial << "Spurious " << _HEX(in_byte) << endl;
-			state = Error;
+			reset();
 			break;
 	}
-	if (curr-buffer > 250)
+	if (buffer.length() > 256)	// TODO magic 256 ?
 	{
-		debug("Spurious byte " << _HEX(in_byte));
-		curr=buffer;
+		debug("Too long");
+		reset();
 	}
 }
 
@@ -496,29 +494,26 @@ void MqttMessage::encodeLength(char* msb, int length)
 
 void MqttMessage::sendTo(MqttClient* client)
 {
-	if (curr-buffer-2 >= 0)
+	if (buffer.size()>2)
 	{
-		encodeLength(buffer+1, curr-buffer-2);
+		encodeLength(&buffer[1], buffer.size()-2);
 		// hexdump("snd");
-		client->write(buffer, curr-buffer);
+		client->write(&buffer[0], buffer.size());
 	}
 	else
 	{
 		Serial << "??? Invalid send" << endl;
-		Serial << (long)end() << "-" << (long)buffer << endl;
 	}
 }
 
 void MqttMessage::hexdump(const char* prefix) const
 {
 	if (prefix) Serial << prefix << ' ';
-	Serial << (long)buffer << "-" << (long)curr << " : ";
-		const char* p=buffer;
-		while(p!=curr)
+	Serial << "size(" << buffer.size() << ") : ";
+		for(const char chr: buffer)
 		{
-			if (*p<16) Serial << '0';
-			Serial << _HEX(*p) << ' ';
-			p++;
+			if (chr<16) Serial << '0';
+			Serial << _HEX(chr) << ' ';
 		}
 		Serial << endl;
 }
diff --git a/src/TinyMqtt.h b/src/TinyMqtt.h
index f5a392e..0d927cb 100644
--- a/src/TinyMqtt.h
+++ b/src/TinyMqtt.h
@@ -51,15 +51,15 @@ class MqttMessage
 		void add(const char* p, size_t len);
 		void add(const std::string& s) { add(s.c_str(), s.length()); }
 		void add(const Topic& t) { add(t.str()); }
-		char* getVHeader() const { return vheader; }
-		char* end() const { return curr; }
-		uint16_t length() const { return curr-buffer; }
+		const char* end() const { return &buffer[0]+buffer.size(); }
+		const char* getVHeader() const { return &buffer[vheader]; }
+		uint16_t length() const { return buffer.size(); }
 
 		void reset();
 
 		// buff is MSB/LSB/STRING
 		// output buff+=2, len=length(str)
-		void getString(char* &buff, uint16_t& len);
+		static void getString(const char* &buff, uint16_t& len);
 
 
 		Type type() const
@@ -69,9 +69,9 @@ class MqttMessage
 
 		void create(Type type)
 		{
-			buffer[0]=type;
-			curr=buffer+2;
-			vheader=curr;
+			buffer=(char)type;
+			buffer+='\0';
+			vheader=2;
 			size=0;
 			state=Create;
 		}
@@ -81,9 +81,8 @@ class MqttMessage
 	private:
 		void encodeLength(char* msb, int length);
 
-	  char buffer[256];	// TODO why 256 ? (should be replaced by a std::string)
-		char* vheader;
-		char* curr;
+		std::string buffer;
+		uint8_t vheader;
 		uint16_t size;	// bytes left to receive
 		State state;
 };
@@ -169,26 +168,6 @@ class MqttClient
 		CallBack callback = nullptr;
 };
 
-/***********************************************
- * R1 - accept external cnx
- * R2 - allows all clients pusblish to go outside
- * R3 - allows ext publish to all clients
- * R4 - allows local publish to local clients
- * R5 - tries to connect elsewhere (*)
- * R6 - disconnect external clients
- * R7 - allows all publish to go everywhere
- * ---------------------------------------------
- *  (*) single client or ip range
- * ---------------------------------------------
- *
- * ================================================+
- *              | connected     | not connected    |
- * -------------+---------------+------------------+
- * proxy broker | R2 R3 R5 R6   |    R5 R7         |
- * normal broker| R2 R3 R5 R6   | R1 R5 R7         |
- * -------------+---------------+------------------+
- *
- */
 class MqttBroker
 {
 	enum State