Troubleshooting Google Service Issues with QUIC and Secure Web Gateways

For users of Cisco Umbrella's AnyConnect Secure Mobility Client integrated 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 interaction between the QUIC protocol and the SWG. Let's delve into the specifics of this issue and explore effective solutions.

What is QUIC and Why Does It Cause Problems?

QUIC (Quick UDP Internet Connections) is a network protocol developed by Google, designed 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 and efficiency benefits, it can clash with certain security configurations.

The AnyConnect Secure Mobility Client, when used with a Secure Web Gateway, might not fully support UDP-based requests. This means that when Google Chrome (or other browsers) attempts to use QUIC to connect to Google services, these requests may bypass the SWG proxy, leading to various issues.

Common Symptoms of QUIC-Related Problems

If QUIC is interfering with your SWG, you might observe the following symptoms:

• Google sites or other sites using QUIC fail to load completely or experience intermittent loading issues.
• SWG settings, such as application control and advanced application control (e.g., file uploads), are not applied to these sites.
• Policy enforcement is inconsistent or absent for websites utilizing QUIC.

An example of such an error is shown when a YouTube video fails to load, indicating a potential QUIC-related issue.

Verifying if QUIC is Enabled in Chrome

Before diving into solutions, it's essential to confirm whether QUIC is indeed enabled in your Google Chrome browser. Here’s how to check:

1. Open Chrome Developer Tools: Access it via Menu > More tools > Developer tools, or by pressing Ctrl+Shift+I.
2. Enable Protocol Column: In the Network tab, right-click any column heading and select "Protocol" to include it in the display.
3. Browse to a Google Website: Visit a Google-owned website like https://www.google.com.
4. Check the Protocol Column: Look for the entry http/2+quic/39 in the Protocol column. Its presence confirms that Google QUIC is enabled.

Solutions to Resolve QUIC and SWG Conflicts

If QUIC is causing problems, here are effective solutions to mitigate the issues:

1. Disabling QUIC in Google Chrome

One of the most straightforward solutions is to disable QUIC directly within Google Chrome. You can do this manually or through group policies for managed devices.

Manual Method:

1. Type chrome://flags#enable-quic in the address bar.
2. Set the "Experimental QUIC protocol" flag to "Disabled."
3. Relaunch Chrome for the changes to take effect.

Using Group Policy (GPO):

For managed environments, you can use the following Windows registry key (or Mac/Linux preference) to disable QUIC in Chrome:

• Windows Registry Location (Clients): HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome
• Windows Registry Location (Chrome OS): HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\ChromeOS
• Value Name (REG_DWORD): QuicAllowed

Set the value to 0 (Decimal) or 0x00000000 (Hexadecimal) to disable QUIC.

2. Blocking QUIC on Your Firewall

Another approach is to block the QUIC protocol at the firewall level. This can be achieved by:

• Blocking UDP port 443.
• Blocking QUIC by application name if your firewall supports Layer 7 filtering.

Ensure you allow Umbrella-related IP addresses in your firewall rules to maintain encrypted DNS functionality. Refer to Secure Web Gateway's IP List and Domains to Allow in Customer Firewalls for the necessary IP addresses.

3. Managing QUIC in Other Web Browsers

Besides Chrome, other browsers also support QUIC. Here’s how to manage it in Firefox and Microsoft Edge:

• Firefox: Control QUIC via the network.http.http3.enabled configuration option by typing about:config in the URL bar. More information can be found here.
• MS Edge: QUIC can be managed through Group Policy.

Additional Resources

For further troubleshooting and information, consider exploring these related resources:

• Using DNS over HTTPS (DoH) with Umbrella
• Umbrella Diagnostic Tool

By understanding the interaction between QUIC and Secure Web Gateways, and implementing the appropriate solutions, you can ensure seamless access to Google services while maintaining robust security measures.