The HTTPS DNS Resolution Feature
Google Chrome is constantly updating its underlying networking stack to improve privacy and connection speed. One of the experimental features involves the ALPN (Application-Layer Protocol Negotiation) extension within the TLS handshake. Specifically, the “Use DNS https alpn” flag allows Chrome to query the Domain Name System (DNS) for HTTPS records that contain ALPN parameters. This theoretically allows Chrome to know in advance whether a server supports modern, faster protocols like HTTP/3 (QUIC) before it even attempts to establish a connection, bypassing the need for a slower upgrade process.
However, because this involves querying DNS records for non-standard or relatively new HTTPS parameters, it can cause severe connection issues on strictly managed enterprise networks. If your corporate firewall, local proxy, or aggressive antivirus software intercepts and inspects DNS queries but does not recognize the ALPN record type, it may drop the packets entirely. This results in Chrome failing to resolve specific websites, showing frustrating ERR_NAME_NOT_RESOLVED or connection timeout errors. If you are experiencing strange DNS failures on a restricted network, you should disable this predictive querying.
How to Turn Off DNS HTTPS ALPN
You can force Chrome to use standard DNS resolution via the experimental flags menu.
- Open Google Chrome.
- Click inside the main address bar at the top of the browser.
- Type
chrome://flagsand press Enter. - A page titled “Experiments” will load.
- In the search bar at the top, type Use DNS https alpn.
- The specific flag will appear highlighted in yellow. Next to it is a dropdown menu.
- Change the dropdown menu setting from “Default” to Disabled.
- Click the blue Relaunch button at the bottom of the screen.
Upon restarting, Chrome will stop querying DNS servers for advanced ALPN HTTPS records, ensuring maximum compatibility with older or highly restrictive network firewalls.