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Using Chrome’s Net Export Tool for Network Diagnostics

Using Chrome’s Net Export Tool for Network Diagnostics

Kerry Cordero
Laptops & DesktopsRouting & SwitchingSecurityServers
3 min read

As network engineers, we often find ourselves at the crossroads of application and infrastructure troubleshooting. While packet captures and network monitoring tools like Wireshark or Splunk are our go-to resources, sometimes the problem lies closer to the end user—right in their browser. Enter Chrome’s Net Export Tool, an underutilized but incredibly powerful resource for diagnosing browser-related network issues.

What is chrome://net-export/?

Google Chrome’s chrome://net-export/ is a built-in diagnostic tool that allows you to capture and analyze detailed logs of all network activity initiated by the browser. It provides insights into DNS lookups, SSL handshakes, HTTP requests and responses, proxy settings, and more.

For network engineers, this tool is invaluable when debugging issues like:

  • Slow page loads.
  • SSL/TLS handshake errors.
  • Failed API calls due to CORS policies or other misconfigurations.
  • Connectivity issues between the browser and backend services.

Why Should Network Engineers Care?

When users report issues accessing web-based applications, the problem isn’t always with the network. The issue might originate from the application layer or even the browser itself. By capturing a network log, we can:

  • Validate whether requests are reaching the backend servers.
  • Analyze response times and error codes.
  • Identify misconfigured DNS or proxy settings.
  • Correlate browser errors with network events.

Getting Started with chrome://net-export/

Step 1: Open the Net Export Tool

  1. Launch Google Chrome.
  2. Type chrome://net-export/ into the address bar and press Enter.
  3. You’ll see the Net Export interface, which is simple and straightforward.

You should see something like below:

OPTIONS: This section should normally be left alone.

  • Strip private information
  • Include cookies and credentials
  • Include raw bytes (will include cookies and credentials)

Maximum log size (megabytes):  (Blank means unlimited)

Step 2: Start Logging

  1. Click Start Logging to Disk.
  2. Select a location to save the log file. The log will be saved as a .json file.
  3. (Optional) Set a custom logging mode by clicking on the Capture Mode drop-down menu. For most use cases, the default mode is sufficient.

Step 3: Reproduce the Issue

While logging is active, perform the actions that trigger the problem:

  • Try accessing the problematic website or web app.
  • Navigate through the steps until the issue occurs.

Step 4: Stop Logging

  1. Return to the chrome://net-export/ tab.
  2. Click Stop Logging to finish capturing network activity.

Analyzing the Logs

The .json file produced by the Net Export tool is not meant to be read directly. Instead, use the NetLog Viewer for a visual and searchable interface.

Steps to Analyze the Log:

  1. Open NetLog Viewer.
  2. Click Choose File and upload the .json log file.
  3. Use the timeline view to analyze:
    • DNS Lookups: Identify delays or failures.
    • SSL Handshakes: Pinpoint certificate or cipher issues.
    • HTTP Requests and Responses: Track errors like 404, 500, or 504 Gateway Timeout.

https://netlog-viewer.appspot.com/#import

Command Examples for Engineers

Here’s how you can apply the Net Export tool to real-world scenarios:

Verifying DNS Resolution

When users complain about a site not loading:

  • Check the timeline for DNS lookup delays or failures.
  • Cross-reference the DNS query with nslookup or dig from your terminal.
# Example of verifying DNS records
nslookup www.example.com
dig www.example.com

Diagnosing SSL/TLS Errors

If users report “Your connection is not private” errors:

  • Use the NetLog Viewer to analyze the SSL handshake.
  • Look for issues like invalid certificates or mismatched ciphers.
  • Confirm server-side SSL configuration using tools like openssl.
# Verify SSL handshake
openssl s_client -connect www.example.com:443

Debugging Slow Load Times

  • Identify slow API calls or resources by filtering for requests with high latency.
  • Compare response times with the server logs to determine where the delay occurs.

Best Practices for Capturing Logs

  1. Start with a Fresh Browser Session: Use Incognito Mode to eliminate interference from browser extensions or cached data.
  2. Isolate the Problem: Minimize unrelated browsing activity while capturing logs to reduce noise.
  3. Secure the Data: Review the log before sharing, as it may include sensitive information like cookies or authentication tokens.

When to Use Net Export Over Other Tools

While tools like Wireshark provide packet-level details, chrome://net-export/ focuses on application-layer insights. Use it when:

  • The issue is isolated to specific web applications.
  • You need to confirm browser-specific behavior.
  • Troubleshooting HTTP, HTTPS, or WebSocket connections.

Conclusion

For network engineers, chrome://net-export/ bridges the gap between browser-level troubleshooting and deeper network diagnostics. It’s a lightweight, effective way to capture and analyze browser network activity without deploying additional tools.

Don’t stop at the packet capture next time a user reports an issue. Use Chrome’s Net Export tool to trace the issue from the client side to the backend. It’s another arrow in your troubleshooting quiver, helping you solve problems faster and more efficiently.

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