diff --git a/lib/nodes/mqtt.c b/lib/nodes/mqtt.c
index 455e0d419..17dca2585 100644
--- a/lib/nodes/mqtt.c
+++ b/lib/nodes/mqtt.c
@@ -28,10 +28,13 @@
 #include <villas/utils.h>
 #include <villas/format_type.h>
 
+//#define MQTT_THREAD 1
+
 #ifdef MQTT_THREAD
 #include <pthread.h>
 
 static struct {
+	pthread_t thread;
 	pthread_mutex_t mutex;
 	int length;
 	struct pollfd *fds;
@@ -46,7 +49,7 @@ static pthread_t thread;
 
 static int mqtt_register_client(struct mosquitto *mosq)
 {
-//	pthread_mutex_lock(&polling.mutex);
+	pthread_mutex_lock(&polling.mutex);
 
 	/* Add this client to the pollfd list */
 	int i = polling.length++;
@@ -55,7 +58,7 @@ static int mqtt_register_client(struct mosquitto *mosq)
 	polling.clients = realloc(polling.clients, polling.length * sizeof(struct mosquitto *));
 
 	if (!polling.fds || !polling.clients) {
-//	pthread_mutex_unlock(&polling.mutex);
+		pthread_mutex_unlock(&polling.mutex);
 		return -1;
 	}
 
@@ -63,14 +66,16 @@ static int mqtt_register_client(struct mosquitto *mosq)
 	polling.fds[i].events = POLLIN;
 	polling.fds[i].fd = mosquitto_socket(mosq);
 
-//	pthread_mutex_unlock(&polling.mutex);
+	pthread_mutex_unlock(&polling.mutex);
+
+	info("MQTT: registered new client");
 
 	return 0;
 }
 
 static int mqtt_unregister_client(struct mosquitto *mosq)
 {
-//	pthread_mutex_lock(&polling.mutex);
+	pthread_mutex_lock(&polling.mutex);
 
 	/* Find client */
 	int i;
@@ -80,7 +85,7 @@ static int mqtt_unregister_client(struct mosquitto *mosq)
 	}
 
 	if (i >= polling.length) {
-//		pthread_mutex_unlock(&polling.mutex);
+		pthread_mutex_unlock(&polling.mutex);
 		return -1; /* Otherwise something wrong happened! */
 	}
 
@@ -90,7 +95,9 @@ static int mqtt_unregister_client(struct mosquitto *mosq)
 
 	polling.length--;
 
-//	pthread_mutex_unlock(&polling.mutex);
+	pthread_mutex_unlock(&polling.mutex);
+
+	info("MQTT: deregistered client");
 
 	return 0;
 }
@@ -155,7 +162,9 @@ static void mqtt_connect_cb(struct mosquitto *mosq, void *userdata, int result)
 
 	debug(5, "MQTT: Node %s connected to broker %s", node_name(n), m->host);
 
-//	mqtt_register_client(mosq);
+#ifdef MQTT_THREAD
+	mqtt_register_client(mosq);
+#endif
 }
 
 static void mqtt_disconnect_cb(struct mosquitto *mosq, void *userdata, int result)
@@ -165,7 +174,9 @@ static void mqtt_disconnect_cb(struct mosquitto *mosq, void *userdata, int resul
 
 	debug(5, "MQTT: Node %s disconnected from broker %s", node_name(n), m->host);
 
-//	mqtt_unregister_client(mosq)
+#ifdef MQTT_THREAD
+	mqtt_unregister_client(mosq);
+#endif
 }
 
 static void mqtt_message_cb(struct mosquitto *mosq, void *userdata, const struct mosquitto_message *msg)
@@ -390,10 +401,6 @@ int mqtt_start(struct node *n)
 	if (ret)
 		return ret;
 
-	ret = mosquitto_connect(m->client, m->host, m->port, m->keepalive);
-	if (ret)
-		return ret;
-
 #ifdef MQTT_THREAD
 	mqtt_register_client(m->client);
 #else
@@ -402,6 +409,10 @@ int mqtt_start(struct node *n)
 		return ret;
 #endif
 
+	ret = mosquitto_connect(m->client, m->host, m->port, m->keepalive);
+	if (ret)
+		return ret;
+
 	ret = mosquitto_subscribe(m->client, NULL, m->subscribe, m->qos);
 	if (ret)
 		return ret;