使用Flask与Ngrok时发送认证请求失败，求排查解决

我编写了一段测试Webhook监听器的Flask代码，运行正常，但执行ngrok http 4242时会话一直处于「reconnecting (failed to send authentication request: session closed)」状态。运行ngrok diagnose后检测到TLS相关错误（NGROK_ERR_8001、NGROK_ERR_8003），具体信息如下：

Flask测试代码 #

from flask import Flask, request, Response

app = Flask(__name__)

@app.route('/', methods=['POST','GET'])
def return_response():
    print(request.json);
    return Response(status=200)

@app.route('/webhook', methods=['POST'])
def response():
    print(request.json);
    return Response(status=200)

if __name__ == "__main__": app.run(debug=True, port=4242, host='10.1.10.112')

Ngrok错误输出 #

ngrok                                                                                                                                             (Ctrl+C to quit)                                                                                                                                                                  
Session Status                reconnecting (failed to send authentication request: session closed)                                                                 
Version                       3.3.0                                                                                                                               
Latency                       -                                                                                                                                    
Web Interface                 http://127.0.0.1:4040                                                                                                               
                                                                                                                                                                  
Connections                   ttl     opn     rt1     rt5     p50     p90                                                                                         
                              0       0       0.00    0.00    0.00    0.00   

Ngrok诊断输出 #

Testing ngrok connectivity...

Internet Connectivity Name Resolution [ OK ] TCP [ OK ] TLS [ WARN ]

Errors and warnings encountered during diagnostics:

• Diagnostics * Connectivity
  • Err: Failed to establish internet connectivity: could not establish any TLS connections (NGROK_ERR_8001)
  • google.com (142.250.207.78:443)
    • Err: Failed to establish TLS connection to 142.250.207.78 with error: context deadline exceeded. Possible Man-in-the Middle. (NGROK_ERR_8003)
  • google.com (142.250.66.78:443)
    • Err: Failed to establish TLS connection to 142.250.66.78 with error: dial tcp 142.250.66.78:443: i/o timeout. Possible Man-in-the Middle. (NGROK_ERR_8003)
  • google.com (142.250.66.46:443)
    • Err: Failed to establish TLS connection to 142.250.66.46 with error: dial tcp 142.250.66.46:443: i/o timeout. Possible Man-in-the Middle. (NGROK_ERR_8003)

Error establishing ngrok connection: Failed to establish internet connectivity: could not establish any TLS connections (NGROK_ERR_8001)
Report written to /tmp/ngrok-diagnose3756442921/diagnose.json

排查原因与解决办法 #

原因分析 #

这些错误本质是TLS连接无法正常建立，常见触发因素：

1. 网络环境存在代理、防火墙或VPN拦截了TLS流量
2. 本地网络DNS解析正常，但TCP握手超时，可能是运营商限制或路由问题
3. 系统存在恶意软件或中间人攻击（MITM）篡改TLS连接

解决步骤 #

• 检查网络环境：关闭VPN、代理工具，暂时禁用防火墙（仅测试用，测试后恢复），重新运行ngrok http 4242
• 切换网络：尝试连接手机热点，排除本地局域网或运营商的限制
• 更新ngrok版本：当前使用的是3.3.0，替换为最新稳定版，旧版本可能存在兼容性问题
• 检查系统证书：确认本地根证书库正常，若存在自定义证书（如公司MITM证书），需将其添加到ngrok的信任列表中
• 切换ngrok模式：尝试ngrok tcp 4242绕开TLS相关拦截，或指定ngrok使用其他端口通信
• 验证本地TLS连接：手动执行curl -v https://google.com测试TLS连接，确认是否是系统层面的问题而非ngrok单独的问题

内容的提问来源于stack exchange，提问作者Quyễn Nguyễn