Fix IPv6 trace: use node:https with family option instead of IP literal fetch (1.1.1)

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

CHANGELOG.md

@@ -3,10 +3,17 @@
 All notable changes to this project are documented here, newest first.
 Every change is committed and pushed so the history can be followed in git as well.
 
+## [1.1.1] - 2026-09-08
+
+### Fixed
+- IPv6 trace showed `n/a (fetch failed)`: Node's `fetch` (undici) mangles IPv6 literals during TLS
+  hostname verification. The check now uses `node:https` with the `family` option against
+  `www.cloudflare.com`, so both families work with normal certificate validation.
+
 ## [1.1.0] - 2026-09-08
 
 ### Changed
-- WARP check now queries Cloudflare over IPv4 and IPv6 separately (by edge IP literal) and logs both
+- WARP check now queries Cloudflare over IPv4 and IPv6 separately and logs both
   egress IPs: `ipv4=104.28.x.x (warp=on) ipv6=2a09:bac1:... (warp=on) colo=AMS loc=NL`.
 - `/warp` slash command shows the IPv4 and IPv6 Cloudflare IPs on separate lines.
 - "Connected" now means the IPv4 path (the one Discord uses) reports `warp=on`; IPv6 is informational.

README.md

@@ -27,7 +27,7 @@ generated inside a `node:22-bookworm-slim` container.
 2. It then calls `https://www.cloudflare.com/cdn-cgi/trace` and **refuses to start the bot** unless
    Cloudflare reports `warp=on` (or `warp=plus`). The egress IP and colo are logged.
 3. `bot/src/index.js` logs into Discord and every `WARP_CHECK_INTERVAL` seconds (default 60) asks
-   Cloudflare's edge over IPv4 (`1.1.1.1`) and IPv6 (`2606:4700:4700::1111`) what it sees, logging a line like:
+   Cloudflare once over IPv4 and once over IPv6 what it sees, logging a line like:
 
    ```
    [2026-09-08T00:20:15.123Z] [WARP] CONNECTED via Cloudflare (periodic) ipv4=104.28.x.x (warp=on) ipv6=2a09:bac1:xxxx::x:x (warp=on) colo=AMS loc=NL | warp-cli: Status update: Connected Network: healthy

bot/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "discordbot-cloudflarewarp",
-  "version": "1.1.0",
+  "version": "1.1.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "discordbot-cloudflarewarp",
-      "version": "1.1.0",
+      "version": "1.1.1",
       "license": "MIT",
       "dependencies": {
         "discord.js": "^14.16.3"

bot/package.json

@@ -1,6 +1,6 @@
 {
   "name": "discordbot-cloudflarewarp",
-  "version": "1.1.0",
+  "version": "1.1.1",
   "description": "Simple discord.js bot that runs behind a Cloudflare WARP tunnel and logs the Cloudflare IP it uses",
   "main": "src/index.js",
   "type": "module",

bot/src/index.js

@@ -1,4 +1,5 @@
 import { execFile } from "node:child_process";
+import https from "node:https";
 import { promisify } from "node:util";
 import {
   Client,
@@ -16,10 +17,10 @@ const GUILD_ID = process.env.GUILD_ID || "";
 const CHECK_INTERVAL_SEC = Number(process.env.WARP_CHECK_INTERVAL || 60);
 
 // Cloudflare's trace endpoint reports the IP it sees us as and whether the
-// request arrived over WARP. Hitting the edge by IP literal lets us force the
-// address family so both the IPv4 and IPv6 egress IPs can be shown.
-const TRACE_V4 = "https://1.1.1.1/cdn-cgi/trace";
-const TRACE_V6 = "https://[2606:4700:4700::1111]/cdn-cgi/trace";
+// request arrived over WARP. The request is made once per address family so
+// both the IPv4 and the IPv6 Cloudflare egress IPs can be shown.
+const TRACE_HOST = "www.cloudflare.com";
+const TRACE_PATH = "/cdn-cgi/trace";
 
 if (!TOKEN) {
   console.error("[bot] DISCORD_TOKEN is not set. Exiting.");
@@ -47,16 +48,30 @@ function parseTrace(text) {
   return data;
 }
 
-async function fetchTrace(url) {
-  const res = await fetch(url, { signal: AbortSignal.timeout(10_000) });
-  if (!res.ok) throw new Error(`trace HTTP ${res.status}`);
-  return parseTrace(await res.text());
+/** GET the trace endpoint over a specific IP family (4 or 6). */
+function fetchTrace(family) {
+  return new Promise((resolve, reject) => {
+    const req = https.get(
+      { host: TRACE_HOST, path: TRACE_PATH, family, timeout: 10_000 },
+      (res) => {
+        let body = "";
+        res.setEncoding("utf8");
+        res.on("data", (c) => (body += c));
+        res.on("end", () => {
+          if (res.statusCode !== 200) return reject(new Error(`trace HTTP ${res.statusCode}`));
+          resolve(parseTrace(body));
+        });
+      }
+    );
+    req.on("timeout", () => req.destroy(new Error("timeout")));
+    req.on("error", reject);
+  });
 }
 
 /** Returns { ok, ip, warp, colo, loc, error } for one address family. */
-async function traceFamily(url) {
+async function traceFamily(family) {
   try {
-    const t = await fetchTrace(url);
+    const t = await fetchTrace(family);
     return { ok: t.warp === "on" || t.warp === "plus", ...t };
   } catch (err) {
     return { ok: false, error: err.message };
@@ -81,8 +96,8 @@ let lastWarp = null;
 
 async function checkWarp(reason = "periodic") {
   const [v4, v6, cliStatus] = await Promise.all([
-    traceFamily(TRACE_V4),
-    traceFamily(TRACE_V6),
+    traceFamily(4),
+    traceFamily(6),
     warpCliStatus(),
   ]);