diff --git a/packet.go b/packet.go
index e2273b0..231df19 100644
--- a/packet.go
+++ b/packet.go
@@ -31,11 +31,44 @@ type Packet struct {
 	StatusCode  uint32
 }
 
+var headerData = make([]byte, 4)
+
+func matchHeader(conn io.Reader) error {
+
+	pos := 0
+	for pos < 4 {
+
+		l, err := conn.Read(headerData)
+		if err != nil {
+			return err
+		}
+		for i := 0; i < l; i++ {
+			if headerData[i] == header[pos] {
+				pos++
+				if pos == 4 {
+					return nil
+				}
+			} else {
+				pos = 0
+			}
+		}
+	}
+	return nil
+}
+
 func ReadPacket(conn io.Reader, packet *Packet) error {
+	err := matchHeader(conn)
+	if err != nil {
+		return err
+	}
 	return binary.Read(conn, binary.LittleEndian, packet)
 }
 
 func ReadCartPacket(conn io.Reader, packet *CartPacket) error {
+	err := matchHeader(conn)
+	if err != nil {
+		return err
+	}
 	return binary.Read(conn, binary.LittleEndian, packet)
 }
 
diff --git a/tcp-cart-client.go b/tcp-cart-client.go
index 36458c1..52adb02 100644
--- a/tcp-cart-client.go
+++ b/tcp-cart-client.go
@@ -48,7 +48,7 @@ func NewCartTCPClient(address string) (*CartTCPClient, error) {
 }
 
 func (m *CartTCPClient) SendPacket(messageType CartMessage, id CartId, data []byte) error {
-
+	m.Conn.Write(header[:])
 	err := binary.Write(m.Conn, binary.LittleEndian, CartPacket{
 		Version:     CurrentPacketVersion,
 		MessageType: messageType,
diff --git a/tcp-cart-mux-server.go b/tcp-cart-mux-server.go
index 7a58f48..51433e2 100644
--- a/tcp-cart-mux-server.go
+++ b/tcp-cart-mux-server.go
@@ -70,7 +70,7 @@ func (m *TCPCartServerMux) handleFunction(connection net.Conn, messageType CartM
 	m.mu.RUnlock()
 	if ok {
 		responseType, responseData, err := fn(id, data)
-
+		connection.Write(header[:])
 		if err != nil {
 			errData := []byte(err.Error())
 			err = binary.Write(connection, binary.LittleEndian, CartPacket{
@@ -96,6 +96,8 @@ func (m *TCPCartServerMux) handleFunction(connection net.Conn, messageType CartM
 		packetsSent.Inc()
 		_, err = connection.Write(responseData)
 		return true, err
+	} else {
+		log.Printf("No cart handler for type: %d\n", messageType)
 	}
 	return false, nil
 }
diff --git a/tcp-cart_test.go b/tcp-cart_test.go
index 5794d0c..74a7433 100644
--- a/tcp-cart_test.go
+++ b/tcp-cart_test.go
@@ -23,23 +23,24 @@ func TestCartTcpHelpers(t *testing.T) {
 		return nil
 	})
 	server.HandleCall(666, func(id CartId, data []byte) (CartMessage, []byte, error) {
-		log.Printf("Received call: %s\n", string(data))
+		log.Printf("Received 666 call: %s\n", string(data))
 		return 3, []byte("Hello, client!"), fmt.Errorf("Det blev fel")
 	})
 	server.HandleCall(2, func(id CartId, data []byte) (CartMessage, []byte, error) {
-		log.Printf("Received call: %s\n", string(data))
-		return 3, []byte("Hello, client!"), nil
+		log.Printf("Received 2 call: %s\n", string(data))
+		return 4, []byte("Hello, client!"), nil
 	})
 	// server.HandleCall(Ping, func(id CartId, data []byte) (CartMessage, []byte, error) {
 	// 	return Pong, nil, nil
 	// })
 	id := ToCartId("kalle")
 	client.SendPacket(1, id, []byte("Hello, world!"))
-	answer, err := client.Call(2, id, 3, []byte("Hello, server!"))
+	answer, err := client.Call(2, id, 4, []byte("Hello, server!"))
 	if err != nil {
 		t.Errorf("Error calling: %v\n", err)
 	}
 	s, err := client.Call(666, id, 3, []byte("Hello, server!"))
+	client.Close()
 	if err != nil {
 		t.Errorf("Error calling: %v\n", err)
 	}
diff --git a/tcp-client.go b/tcp-client.go
index 6dcf41b..5bb6d33 100644
--- a/tcp-client.go
+++ b/tcp-client.go
@@ -92,8 +92,14 @@ func NewTCPClient(address string) (*TCPClient, error) {
 	}, nil
 }
 
-func (m *TCPClient) SendPacket(messageType PoolMessage, data []byte) error {
+type PacketHeader [4]byte
 
+var (
+	header = PacketHeader([4]byte{0x01, 0x02, 0x03, 0x04})
+)
+
+func (m *TCPClient) SendPacket(messageType PoolMessage, data []byte) error {
+	m.Conn.Write(header[:])
 	err := binary.Write(m.Conn, binary.LittleEndian, Packet{
 		Version:     CurrentPacketVersion,
 		MessageType: messageType,
diff --git a/tcp-mux-server.go b/tcp-mux-server.go
index fa43cfc..ff2f0d3 100644
--- a/tcp-mux-server.go
+++ b/tcp-mux-server.go
@@ -69,6 +69,7 @@ func (m *TCPServerMux) handleFunction(connection net.Conn, messageType PoolMessa
 	function, ok := m.functions[messageType]
 	m.mu.RUnlock()
 	if ok {
+		connection.Write(header[:])
 		responseType, responseData, err := function(data)
 		if err != nil {
 			errData := []byte(err.Error())
@@ -93,6 +94,8 @@ func (m *TCPServerMux) handleFunction(connection net.Conn, messageType PoolMessa
 		packetsSent.Inc()
 		_, err = connection.Write(responseData)
 		return true, err
+	} else {
+		log.Printf("No pool handler for type: %d\n", messageType)
 	}
 	return false, nil
 }