多MQTT客户端连接test.mosquitto.org时遭遇ConnectionRefusedError的问题求助

阿华AIGC实验室

2026-4-21

大家好，我是完全刚接触MQTT协议、Python和paho-mqtt库的新手。我现在想要实现的是两个发布者向同一个主题发送消息，同时一个订阅者监听该主题的所有消息。之前运行订阅者和第一个发布者的时候一切正常，但启动第二个发布者时，就遇到了连接被拒绝的错误，具体报错信息如下：

Traceback (most recent call last):
File "C:\...\MQTT\DigitalTwin2.py", line 14, in <module>
dt_client.connect("test.mosquitto.org", 1883, 60)
File "C:\...\Python\Python39\lib\site-packages\paho\mqtt\client.py", line 914, in connect
return self.reconnect()
File "C:\...\Python\Python39\lib\site-packages\paho\mqtt\client.py", line 1044, in reconnect
sock = self._create_socket_connection()
File "C:\...\Python\Python39\lib\site-packages\paho\mqtt\client.py", line 3685, in _create_socket_connection
return socket.create_connection(addr, timeout=self._connect_timeout, source_address=source)
File "C:\...\Python\Python39\lib\socket.py", line 843, in create_connection
raise err
File "C:\...\Python\Python39\lib\socket.py", line 831, in create_connection
sock.connect(sa)
ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it

我的Python代码如下：
两个发布者的代码几乎完全一致，只有客户端名称不同，以下是发布者的通用代码：

import paho.mqtt.client as mqtt
from random import uniform
import time

def on_dt_connect(client, userdata, flags, rc):
    if rc == 0:
        print("Connected to Digital Twin-1 with result code 0")
    else:
        print("Connection to Digital Twin-1 failed with result code " + str(rc))

dt_client = mqtt.Client("Digital Twin-1")  # 第二个发布者这里是"Digital Twin-2"
dt_client.on_connect = on_dt_connect
dt_client.connect("test.mosquitto.org", 1883, 60)

while True:
    randNumber = uniform(3.0, 4.0)
    randNumber = round(randNumber, 4)
    dt_client.publish("topic", "Digital Twin-1: " + str(randNumber))  # 第二个发布者这里对应改成Digital Twin-2
    print("..." + str(randNumber) + "...")
    time.sleep(1)

订阅者代码：

import paho.mqtt.client as mqtt
import time

def on_sd_connect(client, userdata, flags, rc):
    if rc == 0:
        print("Connected to Smart Device with result code 0")
    else:
        print("Connection to Smart Device failed with result code " + str(rc))

def on_sd_message(client, userdata, message):
    print("...", str(message.payload.decode("utf-8")))

device_client = mqtt.Client("Smart Device")
device_client.on_connect = on_sd_connect
device_client.connect("test.mosquitto.org", 1883, 60)

device_client.loop_start()
device_client.subscribe("topic")
device_client.on_message = on_sd_message

time.sleep(30)
device_client.loop_stop()

我已经查过一些相关问题，但没找到针对三个客户端同时连接场景的解决方案，另外我之前还做过这些操作：