Troubleshoot Chrome network issues

If you experience TCP/IP problems with Chrome browser or a managed ChromeOS device, you can collect network logs and view network data. The network logs are useful if you need to debug network problems, analyze performance, or contact support about a problem.

If an issue seems to be HTTP related, such as 403 errors or missing HTTP headers, use HAR Analyzer.

How to

Get network logs

From Chrome 58 onwards, you can use net-export to export a log file in JavaScript Object Notation (JSON) array format. This log file contains details of Chrome’s network-level events and state.

1. Open a new Chrome browser window and browse to chrome://net-export/
2. (Optional) Select the level of log detail.
   • ​If you don’t change the level of log detail, private information is stripped.
   • To include raw bytes (encrypted or otherwise) that were transmitted over the network, select Include raw bytes (includes cookies and credentials).
3. Click Start logging to disk.
4. Name the file and choose where to save it.
5. Click Save.
6. Open a new tab and re-create the problem.
7. Go back to the net-export tab and click Stop logging.

If a problem occurs before you can browse to chrome://net-export, such as when the Chrome browser or device first starts, use the following command line flag to capture the network log:

--log-net-log=/tmp/mylog.json --net-log-level=0

If you need to, you can change the file path, /tmp/mylog.json.

View network data

1. Open a new Chrome browser window and browse to https://netlog-viewer.appspot.com/#import
   Note: Events are captured immediately. You can see this happening in the red bar at the top of the browser window.
2. Click choose file to import the network log and view information about network events. See the table below for details.

Option	What you can do
Import	Import an exported .json file. Then you can view information about network events.
Proxy	View information about the proxy settings your browser is using. If there's no proxy, you’ll see Use Direct connections.
Events	View a list of events as they occur. Events include socket connections, SPDY sessions, HTTP-TCP connections, and URL requests. Errors display in red text.
Timeline	View a graph with information, such as the number of open or in-use sockets, URL and DNS requests, or how much data has been sent or received.
DNS	View a log of DNS lookups for the device. This can help to troubleshoot issues if webpages fail to load. The log lists the URLs and their corresponding IPs. It also includes the time of the DNS requests.
Sockets	View a log of open and used sockets. Use this log for advanced network troubleshooting.
Alt-Svc	View information about alternate service mappings.
HTTP/2	View a log of HTTP/2 sessions and alternative service mappings.
QUIC	View information about Quick UDP Internet Connections (QUIC). This is an experimental network protocol that optimizes connection-oriented web apps that rely on TCP. You can enable or disable QUIC at chrome://flags/#enable-quic.
Reporting	View origin configurations, network error logging policies, and queued reports.
Cache	See a list of cached entries and statistics.
Modules	View a list of active Chrome extensions and apps.
Prerender	View active prerender websites and their history.
ChromeOS	Capture device logs that are useful for troubleshooting ChromeOS device issues. You can: Import ONC file: Import an Open Network Configuration (ONC) file. Store Logs: Store all device logs in a TGZ file. Perform Network Debugging: Capture logs for specific network interfaces including Wi-Fi, Ethernet, Cellular, and Worldwide Interoperability for Microwave Access (WiMAX). For information about how to examine ChromeOS device logs, see ChromeOS device debug logs.

Related topics

• Collect ChromeOS device debug logs 
• Remote log collection for ChromeOS devices

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