diff --git a/src/handle_connect.c b/src/handle_connect.c
index 088ea051..ad737b8f 100644
--- a/src/handle_connect.c
+++ b/src/handle_connect.c
@@ -132,6 +132,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 	int i;
 	struct mosquitto__security_options *security_opts;
 	mosquitto_property *properties = NULL;
+	mosquitto_property *connack_props = NULL;
 #ifdef WITH_TLS
 	X509 *client_cert = NULL;
 	X509_NAME *name;
@@ -179,7 +180,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 				log__printf(NULL, MOSQ_LOG_INFO, "Invalid protocol version %d in CONNECT from %s.",
 						protocol_version, context->address);
 			}
-			send__connack(db, context, 0, CONNACK_REFUSED_PROTOCOL_VERSION);
+			send__connack(db, context, 0, CONNACK_REFUSED_PROTOCOL_VERSION, NULL);
 			rc = MOSQ_ERR_PROTOCOL;
 			goto handle_connect_error;
 		}
@@ -194,7 +195,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 				log__printf(NULL, MOSQ_LOG_INFO, "Invalid protocol version %d in CONNECT from %s.",
 						protocol_version, context->address);
 			}
-			send__connack(db, context, 0, CONNACK_REFUSED_PROTOCOL_VERSION);
+			send__connack(db, context, 0, CONNACK_REFUSED_PROTOCOL_VERSION, NULL);
 			rc = MOSQ_ERR_PROTOCOL;
 			goto handle_connect_error;
 		}
@@ -238,7 +239,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 
 	if(will && will_retain && db->config->retain_available == false){
 		if(protocol_version == mosq_p_mqtt5){
-			send__connack(db, context, 0, MQTT_RC_RETAIN_NOT_SUPPORTED);
+			send__connack(db, context, 0, MQTT_RC_RETAIN_NOT_SUPPORTED, NULL);
 		}
 		rc = 1;
 		goto handle_connect_error;
@@ -265,7 +266,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 
 	if(slen == 0){
 		if(context->protocol == mosq_p_mqtt31){
-			send__connack(db, context, 0, CONNACK_REFUSED_IDENTIFIER_REJECTED);
+			send__connack(db, context, 0, CONNACK_REFUSED_IDENTIFIER_REJECTED, NULL);
 			rc = MOSQ_ERR_PROTOCOL;
 			goto handle_connect_error;
 		}else{ /* mqtt311/mqtt5 */
@@ -279,7 +280,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 				allow_zero_length_clientid = db->config->security_options.allow_zero_length_clientid;
 			}
 			if(clean_start == 0 || allow_zero_length_clientid == false){
-				send__connack(db, context, 0, CONNACK_REFUSED_IDENTIFIER_REJECTED);
+				send__connack(db, context, 0, CONNACK_REFUSED_IDENTIFIER_REJECTED, NULL);
 				rc = MOSQ_ERR_PROTOCOL;
 				goto handle_connect_error;
 			}else{
@@ -292,6 +293,12 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 					rc = MOSQ_ERR_NOMEM;
 					goto handle_connect_error;
 				}
+				if(context->protocol == mosq_p_mqtt5){
+					if(mosquitto_property_add_string(&connack_props, MQTT_PROP_ASSIGNED_CLIENT_IDENTIFIER, client_id)){
+						rc = MOSQ_ERR_NOMEM;
+						goto handle_connect_error;
+					}
+				}
 			}
 		}
 	}
@@ -299,7 +306,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 	/* clientid_prefixes check */
 	if(db->config->clientid_prefixes){
 		if(strncmp(db->config->clientid_prefixes, client_id, strlen(db->config->clientid_prefixes))){
-			send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED);
+			send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED, NULL);
 			rc = 1;
 			goto handle_connect_error;
 		}
@@ -425,7 +432,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 		password = NULL;
 
 		if(!context->ssl){
-			send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD);
+			send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD, NULL);
 			rc = 1;
 			goto handle_connect_error;
 		}
@@ -433,7 +440,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 		if(context->listener->psk_hint){
 			/* Client should have provided an identity to get this far. */
 			if(!context->username){
-				send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD);
+				send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD, NULL);
 				rc = 1;
 				goto handle_connect_error;
 			}
@@ -441,20 +448,20 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 #endif /* WITH_TLS_PSK */
 			client_cert = SSL_get_peer_certificate(context->ssl);
 			if(!client_cert){
-				send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD);
+				send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD, NULL);
 				rc = 1;
 				goto handle_connect_error;
 			}
 			name = X509_get_subject_name(client_cert);
 			if(!name){
-				send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD);
+				send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD, NULL);
 				rc = 1;
 				goto handle_connect_error;
 			}
 			if (context->listener->use_identity_as_username) { //use_identity_as_username
 				i = X509_NAME_get_index_by_NID(name, NID_commonName, -1);
 				if(i == -1){
-					send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD);
+					send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD, NULL);
 					rc = 1;
 					goto handle_connect_error;
 				}
@@ -462,19 +469,19 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 				if(name_entry){
 					name_asn1 = X509_NAME_ENTRY_get_data(name_entry);
 					if (name_asn1 == NULL) {
-						send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD);
+						send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD, NULL);
 						rc = 1;
 						goto handle_connect_error;
 					}
 					context->username = mosquitto__strdup((char *) ASN1_STRING_data(name_asn1));
 					if(!context->username){
-						send__connack(db, context, 0, CONNACK_REFUSED_SERVER_UNAVAILABLE);
+						send__connack(db, context, 0, CONNACK_REFUSED_SERVER_UNAVAILABLE, NULL);
 						rc = MOSQ_ERR_NOMEM;
 						goto handle_connect_error;
 					}
 					/* Make sure there isn't an embedded NUL character in the CN */
 					if ((size_t)ASN1_STRING_length(name_asn1) != strlen(context->username)) {
-						send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD);
+						send__connack(db, context, 0, CONNACK_REFUSED_BAD_USERNAME_PASSWORD, NULL);
 						rc = 1;
 						goto handle_connect_error;
 					}
@@ -518,7 +525,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 				case MOSQ_ERR_SUCCESS:
 					break;
 				case MOSQ_ERR_AUTH:
-					send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED);
+					send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED, NULL);
 					context__disconnect(db, context);
 					rc = 1;
 					goto handle_connect_error;
@@ -539,7 +546,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 			if((db->config->per_listener_settings && context->listener->security_options.allow_anonymous == false)
 					|| (!db->config->per_listener_settings && db->config->security_options.allow_anonymous == false)){
 
-				send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED);
+				send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED, NULL);
 				rc = 1;
 				goto handle_connect_error;
 			}
@@ -557,7 +564,7 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 				goto handle_connect_error;
 			}
 		}else{
-			send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED);
+			send__connack(db, context, 0, CONNACK_REFUSED_NOT_AUTHORIZED, NULL);
 			rc = 1;
 			goto handle_connect_error;
 		}
@@ -710,7 +717,9 @@ int handle__connect(struct mosquitto_db *db, struct mosquitto *context)
 	}
 #endif
 	context->state = mosq_cs_connected;
-	return send__connack(db, context, connect_ack, CONNACK_ACCEPTED);
+	rc = send__connack(db, context, connect_ack, CONNACK_ACCEPTED, connack_props);
+	mosquitto_property_free_all(&connack_props);
+	return rc;
 
 handle_connect_error:
 	mosquitto__free(client_id);
@@ -721,6 +730,7 @@ handle_connect_error:
 	if(will_struct){
 		mosquitto_property_free_all(&will_struct->properties);
 	}
+	mosquitto_property_free_all(&connack_props);
 	mosquitto__free(will_struct);
 #ifdef WITH_TLS
 	if(client_cert) X509_free(client_cert);
diff --git a/src/mosquitto_broker_internal.h b/src/mosquitto_broker_internal.h
index 3cfe0738..7a1b6bd7 100644
--- a/src/mosquitto_broker_internal.h
+++ b/src/mosquitto_broker_internal.h
@@ -512,7 +512,7 @@ int restore_privileges(void);
 /* ============================================================
  * Server send functions
  * ============================================================ */
-int send__connack(struct mosquitto_db *db, struct mosquitto *context, int ack, int reason_code);
+int send__connack(struct mosquitto_db *db, struct mosquitto *context, int ack, int reason_code, const mosquitto_property *properties);
 int send__suback(struct mosquitto *context, uint16_t mid, uint32_t payloadlen, const void *payload);
 int send__unsuback(struct mosquitto *context, uint16_t mid, const mosquitto_property *properties);
 
diff --git a/src/send_connack.c b/src/send_connack.c
index 0891af60..1c20820c 100644
--- a/src/send_connack.c
+++ b/src/send_connack.c
@@ -23,13 +23,18 @@ Contributors:
 #include "property_mosq.h"
 #include "util_mosq.h"
 
-int send__connack(struct mosquitto_db *db, struct mosquitto *context, int ack, int reason_code)
+int send__connack(struct mosquitto_db *db, struct mosquitto *context, int ack, int reason_code, const mosquitto_property *properties)
 {
 	struct mosquitto__packet *packet = NULL;
 	int rc;
-	mosquitto_property *properties = NULL;
+	mosquitto_property *connack_props = NULL;
 	int proplen, varbytes;
 
+	rc = mosquitto_property_copy_all(&connack_props, properties);
+	if(rc){
+		return rc;
+	}
+
 	if(context){
 		if(context->id){
 			log__printf(NULL, MOSQ_LOG_DEBUG, "Sending CONNACK to %s (%d, %d)", context->id, ack, reason_code);
@@ -45,25 +50,25 @@ int send__connack(struct mosquitto_db *db, struct mosquitto *context, int ack, i
 	packet->remaining_length = 2;
 	if(context->protocol == mosq_p_mqtt5){
 		if(reason_code < 128 && db->config->retain_available == false){
-			rc = mosquitto_property_add_byte(&properties, MQTT_PROP_RETAIN_AVAILABLE, 0);
+			rc = mosquitto_property_add_byte(&connack_props, MQTT_PROP_RETAIN_AVAILABLE, 0);
 			if(rc){
 				mosquitto__free(packet);
 				return rc;
 			}
 		}
 		/* FIXME - disable support until available */
-		rc = mosquitto_property_add_byte(&properties, MQTT_PROP_SHARED_SUB_AVAILABLE, 0);
+		rc = mosquitto_property_add_byte(&connack_props, MQTT_PROP_SHARED_SUB_AVAILABLE, 0);
 		if(rc){
 			mosquitto__free(packet);
 			return rc;
 		}
-		rc = mosquitto_property_add_byte(&properties, MQTT_PROP_SUBSCRIPTION_ID_AVAILABLE, 0);
+		rc = mosquitto_property_add_byte(&connack_props, MQTT_PROP_SUBSCRIPTION_ID_AVAILABLE, 0);
 		if(rc){
 			mosquitto__free(packet);
 			return rc;
 		}
 
-		proplen = property__get_length_all(properties);
+		proplen = property__get_length_all(connack_props);
 		varbytes = packet__varint_bytes(proplen);
 		packet->remaining_length += proplen + varbytes;
 	}
@@ -75,9 +80,9 @@ int send__connack(struct mosquitto_db *db, struct mosquitto *context, int ack, i
 	packet__write_byte(packet, ack);
 	packet__write_byte(packet, reason_code);
 	if(context->protocol == mosq_p_mqtt5){
-		property__write_all(packet, properties);
+		property__write_all(packet, connack_props);
 	}
-	mosquitto_property_free_all(&properties);
+	mosquitto_property_free_all(&connack_props);
 
 	return packet__queue(context, packet);
 }