https://www.drmhse.com/tags/dns/Recent content in Dns on DRM HSEHugoenWed, 15 Jul 2026 23:13:04 +0300https://www.drmhse.com/posts/nginx_stale_dns_resolved_for_domains/Tue, 28 Oct 2025 05:20:09 +0000https://www.drmhse.com/posts/nginx_stale_dns_resolved_for_domains/<p>A literal hostname in <code>proxy_pass</code> can outlive the IP address it first resolved to. The configuration starts cleanly and requests succeed, but replacing the backend later leaves Nginx connecting to the old address. A reload appears to fix the problem because it triggers another lookup.</p> <p>I wanted a local reproduction that separated this DNS behaviour from the rest of a production system. The useful part of the exercise was not just making Nginx return <code>502 Bad Gateway</code>; it was discovering why my first test could not expose the bug.</p>