Windows 10客户端HTTP POST文件上传过慢问题（ASP.NET+IIS环境）

Let me start by breaking down the issue you've reported to make sure we're aligned:

仅Windows 10客户端存在上传缓慢情况。该站点基于ASP.NET部署，通过FileUpload控件与HTTP POST实现文件上传，测试环境为本地PC的IIS服务，仅对内网域名开放。测试用70MB文件，Windows 7客户端上传仅需40秒，而Windows 10客户端需耗时8分钟以上，且两台客户端处于同一域中，该问题已在2台设备上复现。

Since this issue is isolated to Windows 10 and reproducible across multiple devices, it's almost certainly an OS-level network or protocol conflict with your IIS/ASP.NET setup. Here are the most likely fixes to try, ordered by how common they are in this scenario:

1. Check HTTP/2 Compatibility #

Windows 10 enables HTTP/2 by default, while Windows 7 relies on HTTP/1.1. Older IIS or ASP.NET setups can sometimes have compatibility issues with HTTP/2 that lead to slow uploads.

• Disable HTTP/2 on your IIS server:
  1. Open IIS Manager, navigate to your site, and go to Features View
  2. Double-click HTTP Response Headers
  3. Look for an Upgrade header with value h2,h2c
  4. Either remove this header entirely, or modify it to prioritize http/1.1 (e.g., http/1.1,h2)
• Alternatively, force HTTP/1.1 on the Windows 10 client:
  • Edit the registry (make sure to back it up first!):
    1. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters
    2. Create a DWORD value named EnableHttp2Tls and set it to 0
    3. Restart the HTTP service or reboot the client to apply changes

2. Adjust Windows 10 TCP Auto-Tuning #

Windows 10 has more aggressive TCP auto-tuning settings that can sometimes throttle uploads to local servers.

• Disable auto-tuning temporarily to test:
  Open Command Prompt as Administrator and run:

  netsh int tcp set global autotuninglevel=disabled
  

  If this fixes the issue, you can try setting it to normal instead of fully disabling to balance performance while avoiding the throttle.

3. Verify ASP.NET Request Limits #

While Windows 7 works, it's worth double-checking your web.config to ensure it's configured to handle 70MB files without throttling:

<configuration>
  <system.web>
    <!-- Max request length in KB (72MB = 73728 KB) -->
    <httpRuntime maxRequestLength="73728" executionTimeout="3600" />
  </system.web>
  <system.webServer>
    <security>
      <requestFiltering>
        <!-- Max content length in bytes (72MB = 75497472 bytes) -->
        <requestLimits maxAllowedContentLength="75497472" />
      </requestFiltering>
    </security>
  </system.webServer>
</configuration>

The executionTimeout ensures the server doesn't time out before the upload completes on slower connections.

4. Rule Out Windows Defender/Firewall Interference #

Windows 10's Defender has more robust real-time scanning that might be inspecting upload traffic and causing delays.

• Temporarily disable real-time protection (don't forget to turn it back on after testing):
  1. Open Windows Security > Virus & Threat Protection > Manage Settings
  2. Toggle off Real-Time Protection
• Add exclusions for your IIS site:
  If disabling Defender fixes the issue, add the site's physical file path and the IIS worker process (w3wp.exe) to Defender's exclusion list to avoid future conflicts.

5. Tweak Network Adapter Settings #

Some Windows 10 network adapter features can cause upload slowdowns on local networks:

• Disable Large Send Offload (LSO):
  1. Open Device Manager > Network Adapters > Right-click your adapter > Properties
  2. Go to the Advanced tab
  3. Find Large Send Offload Version 2 (IPv4) and set it to Disabled
  4. Repeat for IPv6 if it's enabled
• Reset QoS settings:
  Run Command Prompt as Administrator:

  netsh qos reset
  netsh int tcp set global congestionprovider=ctcp
  

This resets any bandwidth reservation that might be limiting upload speeds.

Start with the first two fixes—HTTP/2 and TCP auto-tuning are the most frequent causes of this exact issue. Let me know if any of these resolve your slow uploads!

内容的提问来源于stack exchange，提问作者1800-Brad-Man