Troubleshooting Google Service Issues with QUIC and Secure Web Gateways

For users of Cisco Umbrella's AnyConnect Secure Mobility Client combined with a Secure Web Gateway (SWG), encountering issues with Google services like Search, Gmail, or YouTube can be a frustrating experience. These problems often stem from the use of the QUIC protocol by Google Chrome and other browsers. This article delves into the technical details of this conflict and provides practical solutions to resolve it.

What is QUIC and Why Does It Cause Problems?

QUIC (Quick UDP Internet Connections) is a network protocol designed by Google to improve the performance of web applications. Unlike the traditional TCP protocol, QUIC uses UDP (User Datagram Protocol) as its transport layer. While QUIC offers speed advantages, it can clash with certain security configurations.

The AnyConnect Secure Mobility Client, when used with a Secure Web Gateway (SWG), may not fully support UDP-based requests like those from QUIC. This means that QUIC-based web requests might bypass the SWG proxy, leading to several issues:

• Failure to Load Google Sites: Websites relying on QUIC may not load correctly or at all.
• SWG Policy Bypass: Security policies, application control, and advanced application control (like upload restrictions) defined in the SWG might not be applied to QUIC traffic.
• Inconsistent Policy Enforcement: Users might experience inconsistent application of security policies, leaving them vulnerable to threats.

Identifying QUIC-Related Issues

Before making any changes, it's important to confirm whether QUIC is indeed the culprit. Google Chrome's Developer Tools provide a straightforward way to check this:

1. Open Developer Tools: In Chrome, go to Menu > More tools > Developer tools (or use the shortcut Ctrl+Shift+I).
2. Enable Protocol Column: In the Network tab, right-click on any column heading and select "Protocol" to add it to the display.
3. Visit a Google Website: Browse to a Google-owned website like google.com.
4. Check the Protocol: Look for the entry "http/2+quic/39" in the Protocol column. If present, QUIC is enabled and likely causing the issues.

Solutions to Resolve QUIC Conflicts

Once you've confirmed that QUIC is causing problems, you can implement the following solutions:

1. Disabling QUIC in Google Chrome

The most direct solution is to disable QUIC within Google Chrome:

• Using Chrome Flags:
  1. In the address bar, type: chrome://flags#enable-quic
  2. Set the "Experimental QUIC protocol" flag to "Disabled."
  3. Relaunch Chrome for the changes to take effect.
• Using Group Policy (GPO) or Registry Settings:
  • For managed devices, you can disable QUIC using Group Policy (GPO) or by directly modifying the Windows Registry.
  • Windows Registry Location (for Chrome clients): HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome
  • Value Name: QuicAllowed (REG_DWORD)
  • Value to Disable QUIC: 0 (Decimal) or 0x00000000 (Hexadecimal)
  • A similar approach can be used for Mac and Linux systems by configuring the corresponding preference.

Disabling QUIC via GPO ensures consistent enforcement across all managed devices.

2. Blocking QUIC on Your Firewall

Alternatively, you can block the QUIC protocol at the firewall level. This can be achieved in two ways:

• Blocking UDP Port 443: Block all UDP traffic on port 443, as this is the standard port used by QUIC.
• Blocking QUIC by Application Name: If your firewall supports Layer 7 (application-level) filtering, block QUIC by its application name.

Important: When blocking QUIC on your firewall, ensure that you allow Umbrella-related IP addresses to facilitate encrypted DNS resolution. Refer to Secure Web Gateway's IP List and Domains to Allow in Customer Firewalls for the complete list.

3. Managing QUIC in Other Browsers

While the primary focus is on Google Chrome, other browsers also support QUIC. Here's how to manage it in Firefox and Microsoft Edge:

• Firefox: Control QUIC using the network.http.http3.enabled configuration option. Type about:config in the URL bar to access the settings. Refer to external resources like this guide for more details.
• Microsoft Edge: Manage QUIC settings through Group Policy.

Conclusion

By understanding the interaction between QUIC, Secure Web Gateways, and the AnyConnect Secure Mobility Client, you can effectively troubleshoot and resolve issues with Google services. Disabling QUIC in browsers or blocking it at the firewall level are viable solutions, each with its own advantages. Remember to consider the impact on user experience and security when implementing these changes. Consulting Cisco Umbrella's official documentation and support resources can provide further assistance.