代理转发至GitHub Pages时突发故障求助

Hey there, let's dig into why your function proxy started throwing this 500 error only for GitHub Pages endpoints, while others like Azure App Service kept working. The key clue from your trace logs is:

"The request was aborted: Could not create SSL/TLS secure channel."

Here are the most likely causes and how to investigate them:

1. TLS Version/Cipher Suite Mismatch #

GitHub Pages might have rolled out a change to their TLS configuration (like dropping support for older TLS versions or less secure cipher suites) during that 8:00-8:30 EST window. While your browser automatically supports modern TLS versions, your function proxy's runtime environment might be stuck on outdated settings that GitHub no longer accepts.

• How to check:
  • Verify what TLS versions your proxy is set to use (ensure it's TLS 1.2 or higher, as TLS 1.0/1.1 are widely deprecated).
  • Compare the cipher suites enabled in your proxy with those currently supported by GitHub Pages. Run a local test from your proxy's environment to see if an HTTPS request to the GitHub Pages endpoint fails with the same SSL error.

2. Outdated Root Certificate Trust Store #

GitHub Pages occasionally updates its SSL certificates or certificate chains. If your proxy's runtime environment hasn't updated its root certificate trust store, it might fail to validate GitHub's new certificate—even though your browser automatically handles these updates in the background.

• How to check:
  • Review the root certificates installed in your proxy's operating system or runtime (e.g., .NET trust store if this is an Azure Functions proxy).
  • Confirm that the certificate authority (CA) issuing GitHub Pages' current SSL certificate is present in your proxy's trust store.

3. Regional GitHub Pages Node Issues #

It's possible that during the failure window, the specific GitHub Pages edge node serving requests from your proxy's region had a temporary SSL handshake problem (like a misconfigured certificate or network glitch). Direct access from your location might have hit a different, fully functional node.

• How to check:
  • Check GitHub's official status updates to see if there were any reported issues with Pages or SSL during that time frame.
  • From your proxy's environment, manually send an HTTPS request to the GitHub Pages endpoint (using tools like curl or Invoke-WebRequest) to see if the SSL error persists.

4. Unusual Request Headers Interfering (Less Likely) #

Looking at your trace logs, the forwarded request includes a lot of extra headers (e.g., CF-*, X-WAWS-*, DISGUISED-HOST). While these shouldn't directly break SSL handshake, in rare cases, unexpected headers might trigger edge-case behavior in GitHub's servers that indirectly causes the SSL connection to fail.

• How to check:
  • Test the proxy with a minimal set of headers (only essential ones like User-Agent, Accept) to see if the connection works. If it does, gradually add back headers to identify which one might be causing the issue.

Next Steps #

Since you've temporarily switched DNS to point directly to GitHub Pages, you can:

• Spin up a small test instance of your proxy to reproduce the issue with detailed SSL logging enabled (if your proxy supports it) to get more granular error details.
• Check if any automatic updates were applied to your proxy's runtime environment around the time of the failure (e.g., OS updates, framework updates that changed SSL settings).

内容的提问来源于stack exchange，提问作者kspearrin