René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"NO_PROXY=example.com does not bypass subdomains for http.request(), unlike fetch()","articleBody":"### Version\n\nv24.18.1, also on main (v27.0.0-pre)\n\n### Platform\n\n```text\nDarwin xxx.local 25.3.0 Darwin Kernel Version 25.3.0: Wed Jan 28 20:54:46 PST 2026; root:xnu-12377.91.3~2/RELEASE_ARM64_T6000 arm64\n```\n\n### Subsystem\n\nhttp\n\n### What steps will reproduce the bug?\n\nDead proxy on port 1 — the error code shows where the request went:\n\n```\nNODE_USE_ENV_PROXY=1 HTTP_PROXY=http://127.0.0.1:1 NO_PROXY=example.com node repro.js\n```\n\n```js\nconst http = require('node:http');\n\nhttp.get('http://internal.example.com/').on('error', (e) => console.log(e.cause?.code ?? e.code));\n// ECONNREFUSED — went through the proxy\n\nfetch('http://internal.example.com/').catch((e) => console.log(e.cause?.code ?? e.code));\n// ENOTFOUND — bypassed, hit DNS\n```\n\n### How often does it reproduce? Is there a required condition?\n\nAlways, when the `NO_PROXY` entry has no leading dot and the request host is a subdomain of that entry.\n\n### What is the expected behavior? Why is that the expected behavior?\n\nSame `NO_PROXY` in the same process should mean the same thing for `http.request()` / `http.get()` and `fetch()`. `http.setGlobalProxyFromEnv()` and the docs present one `NO_PROXY` format for both.\n\n`fetch()` (undici `EnvHttpProxyAgent`) already treats a plain `example.com` as the host and its subdomains, with a label boundary so `notexample.com` does not match. `http` should do the same.\n\n### What do you see instead?\n\n`ProxyConfig#shouldUseProxy` exact-matches a plain entry against the hostname. `NO_PROXY=example.com` therefore does not bypass `internal.example.com` for `http.request()`, while `fetch()` does.\n\nThe docs currently describe this as “Exact host name match”, which matches the `http` implementation and not `fetch()`.\n\n### Additional information\n\nRefs: #57872, #62907","author":{"url":"https://github.com/dibenkobit","@type":"Person","name":"dibenkobit"},"datePublished":"2026-08-28T12:20:38Z","url":"https://github.com/nodejs/node/issues/65616"}