树莓派Mosquitto添加listener配置后无法启动，换端口恢复

问题现象 #

• 树莓派全新安装Mosquitto后，在配置文件/etc/mosquitto/mosquitto.conf末尾添加listener 1883和allow_anonymous true以开启远程访问，服务无法启动
• 执行sudo systemctl status mosquitto查看服务状态，显示启动失败且重启请求过于频繁
• 重新安装Mosquitto后问题依旧，将监听端口改为1884后服务可正常启动，怀疑路由器拦截了1883端口

服务状态信息 #

Loaded: loaded (/lib/systemd/system/mosquitto.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Thu 2022-12-08 12:31:46 CET; 1min 50s ago
Docs: man:mosquitto.conf(5)
man:mosquitto(8)
Process: 630 ExecStartPre=/bin/mkdir -m 740 -p /var/log/mosquitto (code=exited, status=0/SUCCESS)
Process: 631 ExecStartPre=/bin/chown mosquitto /var/log/mosquitto (code=exited, status=0/SUCCESS)
Process: 632 ExecStartPre=/bin/mkdir -m 740 -p /run/mosquitto (code=exited, status=0/SUCCESS)
Process: 633 ExecStartPre=/bin/chown mosquitto /run/mosquitto (code=exited, status=0/SUCCESS)
Process: 634 ExecStart=/usr/sbin/mosquitto -c /etc/mosquitto/mosquitto.conf (code=exited, status=1/FAILURE)
Main PID: 634 (code=exited, status=1/FAILURE)
CPU: 91ms

Dec 08 12:31:46 MyPI systemd[1]: mosquitto.service: Scheduled restart job, restart counter is at 5.
Dec 08 12:31:46 MyPI systemd[1]: Stopped Mosquitto MQTT Broker.
Dec 08 12:31:46 MyPI systemd[1]: mosquitto.service: Start request repeated too quickly.
Dec 08 12:31:46 MyPI systemd[1]: mosquitto.service: Failed with result 'exit-code'.
Dec 08 12:31:46 MyPI systemd[1]: Failed to start Mosquitto MQTT Broker.

配置文件内容 #

# Place your local configuration in /etc/mosquitto/conf.d/
#
# A full description of the configuration file is at
# /usr/share/doc/mosquitto/examples/mosquitto.conf.example
pid_file /run/mosquitto/mosquitto.pid
persistence true
persistence_location /var/lib/mosquitto/
log_dest file /var/log/mosquitto/mosquitto.log
include_dir /etc/mosquitto/conf.d

listener 1883
allow_anonymous true 

排查建议 #

• 检查1883端口是否被其他进程占用：执行sudo lsof -i :1883或sudo netstat -tulpn | grep 1883，若有其他进程占用，会导致Mosquitto无法绑定端口
• 查看Mosquitto日志文件/var/log/mosquitto/mosquitto.log，日志中会包含启动失败的具体原因（比如端口绑定失败的详细提示）
• 路由器拦截1883端口的可能性较低，优先排查本地端口占用、权限配置等问题

内容的提问来源于stack exchange，提问作者ZachL11