> Source: [sk183628](https://support.checkpoint.com/results/sk/sk183628) # sk183628 - HTTPS Inspection is slow when using the Firefox web browser with DoH enabled | Property | Value | |----------|-------| | Solution ID | sk183628 | | Date Created | 2025-07-07 | | Last Modified | 2025-07-07 | | Technical Level | Advanced | | Products | Security Gateway | | Versions | R82.10, R82, R81.20, R81.10 (EOS), R81 (EOS) | | OS | Gaia | ## Symptoms - * HTTPS Inspection is slow when using the Firefox web browser. * The RAD flows report ([sk183416](https://support.checkpoint.com/results/sk/sk183416)) showed an increasing number of the "`Response with wrong status code`" error. * URL Filtering logs in SmartConsole show: `Reason: URL Filtering - Internal system error. (0)` `Action Reason: Blocking request as configured in engine settings of URL Filtering` * The HTTPS web traffic passes normally when using Chromium-based web browsers (Chrome, Edge). ## Cause DNS over HTTPS (DoH) is enabled in Firefox. When DoH is enabled in Firefox, it bypasses the DNS resolver in the local operating system. As a result, all DNS queries go directly from Firefox to the DoH server over HTTPS. This creates two main interactions that can break or delay traffic in an environment with SSL/TLS Inspection and strict security controls. See . ## Solution This solution requires authentication. Please log in to view the full solution. --- # Agent Instructions This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products. ## Navigating This Knowledge Base - **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt) - **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml) - **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}` - **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content