"dns_server_failure" error occurs when attempting to access a site

Products

• Cloud Secure Web Gateway - Cloud SWG

Issue/Introduction

When accessing a site (example: https://www.moea.gov.tw/) through Cloud SWG (formerly known as WSS), the exception page returns a "dns_server_failure" error.

 
dns_server_failure

Cause

The Cloud SWG DNS servers are configured to use DNSSEC. If the domain resolution fails when using DNSSEC then Cloud SWG will process the event as a failure, returning an error.

Resolution

For WSS Agent clients and Explicit Proxy:

From the Cloud SWG portal, access the Bypassed Domains list and add the affected domain as a bypassed domain.

For other access methods or to resolve this issue with the domain's DNS resolution, the customer with the business relationship to the website would contact the domain owner so that they can configure the DNS service properly.