Linux open specified port command

1. Open ports

# zone #作用域
# add-port=9400/tcp  #添加端口，格式为：端口/通讯协议
# permanent  #永久生效，没有此参数重启后失效
firewall-cmd --zone=public --add-port=9400/tcp --permanent

2. Restart the firewall (no restart will not take effect)

firewall-cmd --reload

3. Check whether the opening is successful

firewall-cmd --query-port=9400/tcp