Filter - Enabling Enhanced DNS Bypass Protection for Chromebooks

Overview

Users may attempt to bypass Securly Filter by changing the DNS settings on their Chromebook. This could prevent the Securly extension from reaching Securly servers after a device restart, letting students have unfiltered access to the internet.

To prevent this, we provide a Chromebook‑specific configuration that enables an improved DNS bypass detection mechanism in the Securly Chrome extension. When enabled, the extension continuously checks connectivity to your assigned Securly cluster/server. If DNS settings are tampered with (for example, by using a third-party DNS that blocks the Securly server), the extension will detect this and enforce site blocking on the student device.

Configuring Securly extension policy in Google Admin Console 

1. Sign in to the Google Admin Console. 
2. Navigate to Devices > Chrome > Apps & extensions > Users & browsers and select the OU where your student Chromebooks are located from the OU tree on the left. 
   
3. Click your Securly Chrome extension from the App list.
4. In the Policy for extensions field, add: 

{
 "clusterUrl": {
   "Value": "https://useast2-www.securly.com/crextn"
 },
 "dnsBypassCheckV2": {
   "Value": 1
 }
}

Note:  Ensure to use your assigned clusterUrl in value (https://<your cluster>-www.securly.com/crextn). If you are unsure of your cluster, refer to this article. 

If you already have other policies set, just add these two entries instead of replacing everything, and save your changes. It may take a few minutes for the new policy to apply to the devices.

Verifying the configuration

On a student Chromebook in the configured OU:

1. Log in with a student account that has the Securly extension.
2. Open Chrome and visit chrome://policy from the URL field.
   
3. Click the Reload policies. Then, scroll down to the policy list and verify:
   • clusterUrl is present and matches your Securly cluster.
   • dnsBypassCheckV2 is present and set to 1.