server/src/app.ts

@@ -44,6 +44,7 @@ import { imageProxyHandler } from "./imageproxy.js";
 import { SignInError, finish as finishSignIn, needsRefresh, oauthEnabled, refreshTokens, singleServer, start as startSignIn, type TokenSet } from "./oauth.js";
 import { icsProxyHandler } from "./icsproxy.js";
 import { staticHandler } from "./static.js";
+import { mailNode, webmailNode } from "./nodes.js";
 
 type Env = { Variables: { session: LiveSession } };
 
@@ -609,6 +610,12 @@ export function createApp(basePath = config.basePath): Hono<Env> {
     return c.json({ ok: true });
   });
 
+  /* ihasmail-inbuxa: which webmail node this is, and which mail node it talks to (nodes.ts). */
+  api.get("/about/nodes", requireSession, async (c) => {
+    const session = c.get("session");
+    return c.json({ webmail: webmailNode(), mailServer: await mailNode(upstreamFor(session.username)) });
+  });
+
   api.get("/auth/sessions", requireSession, (c) => {
     const session = c.get("session");
     return c.json({ current: session.id, sessions: sessions.listForUser(session.account) });

server/src/config.ts

@@ -296,6 +296,12 @@ export const config = {
    * such a tree, so the default is INBUXA's fork.
    */
   sourceUrl: env("SOURCE_URL", "https://git.coffeylabs.org/inbuxa/ihasmail-inbuxa"),
+  /**
+   * ihasmail-inbuxa: this webmail's own name, shown in Settings > About next
+   * to the mail node it talks to. Set per host by the deploy; empty means the
+   * container's hostname. See nodes.ts.
+   */
+  nodeName: env("NODE_NAME", ""),
   host: env("HOST", "0.0.0.0"),
   port: int("PORT", 8080),
   /**

server/src/nodes.test.ts

@@ -0,0 +1,40 @@
+import { test, beforeEach } from "node:test";
+import assert from "node:assert/strict";
+import { clearNodeCache, mailNode } from "./nodes.js";
+
+/**
+ * About names the mail node by the PTR of the address the server's name
+ * resolves to from the webmail -- the local node, where a host entry pins it.
+ */
+
+beforeEach(() => clearNodeCache());
+
+const lookup = (address: string) => async () => ({ address });
+
+test("the node is named by its address's PTR, without the trailing dot", async () => {
+  const n = await mailNode("https://mail.example.com", lookup("192.0.2.2"), async () => ["mx2.example.com."]);
+  assert.deepEqual(n, { host: "mail.example.com", address: "192.0.2.2", name: "mx2.example.com" });
+});
+
+test("an address without a PTR still shows the address", async () => {
+  const n = await mailNode("https://mail.example.com", lookup("192.0.2.3"), async () => { throw new Error("ENOTFOUND"); });
+  assert.deepEqual(n, { host: "mail.example.com", address: "192.0.2.3", name: null });
+});
+
+test("a name that doesn't resolve says so instead of failing", async () => {
+  let reversed = false;
+  const n = await mailNode("https://mail.example.com", async () => { throw new Error("ENOTFOUND"); }, async () => { reversed = true; return []; });
+  assert.deepEqual(n, { host: "mail.example.com", address: null, name: null });
+  assert.equal(reversed, false);
+});
+
+test("the answer is cached for a minute, then looked up again", async () => {
+  let calls = 0;
+  const count = async () => { calls++; return { address: "192.0.2.1" }; };
+  const rev = async () => ["mail.example.com"];
+  await mailNode("https://mail.example.com", count, rev, 0);
+  await mailNode("https://mail.example.com", count, rev, 59_000);
+  assert.equal(calls, 1);
+  await mailNode("https://mail.example.com", count, rev, 61_000);
+  assert.equal(calls, 2);
+});

server/src/nodes.ts

@@ -0,0 +1,68 @@
+/**
+ * ihasmail-inbuxa: which webmail node answered, and which inbuxa node it talks
+ * to -- shown in Settings > About, for troubleshooting a cluster.
+ *
+ * Not for upstream ihasmail: it only makes sense where one webmail runs per
+ * host, each pinned to its own host's mail node.
+ *
+ * The webmail node is NODE_NAME, set per host by the deploy; without it, the
+ * container's hostname, which is at least distinct. The mail node is worked
+ * out from the address the server's name resolves to *here*, where the host
+ * entry pins it to the local node, named by that address's PTR record (every
+ * node has one: mail/mx2/mx3). The server offers its node name only to
+ * administrators, so asking it would leave everyone else with nothing.
+ */
+import { lookup as dnsLookup, reverse as dnsReverse } from "node:dns/promises";
+import { hostname } from "node:os";
+import { config } from "./config.js";
+
+export interface MailNode {
+  /** The server name the webmail connects to, from its configured URL. */
+  host: string;
+  /** What that name resolves to from this container, or null if it doesn't. */
+  address: string | null;
+  /** The address's PTR name: the node's own name. Null without a PTR. */
+  name: string | null;
+}
+
+export interface Nodes {
+  webmail: string;
+  mailServer: MailNode;
+}
+
+type Lookup = (host: string) => Promise<{ address: string }>;
+type Reverse = (address: string) => Promise<string[]>;
+
+const CACHE_MS = 60_000;
+const cache = new Map<string, { node: MailNode; at: number }>();
+
+export function webmailNode(): string {
+  return config.nodeName || hostname();
+}
+
+export async function mailNode(base: string, lookup: Lookup = dnsLookup, reverse: Reverse = dnsReverse, now = Date.now()): Promise<MailNode> {
+  const host = new URL(base).hostname;
+  const hit = cache.get(host);
+  if (hit && now - hit.at < CACHE_MS) return hit.node;
+  let address: string | null = null;
+  let name: string | null = null;
+  try {
+    address = (await lookup(host)).address;
+  } catch {
+    /* unresolvable: say so rather than fail the page */
+  }
+  if (address) {
+    try {
+      name = (await reverse(address))[0]?.replace(/\.$/, "") ?? null;
+    } catch {
+      /* no PTR */
+    }
+  }
+  const node = { host, address, name };
+  cache.set(host, { node, at: now });
+  return node;
+}
+
+export function clearNodeCache(): void {
+  cache.clear();
+}

web/src/locales/de.ts

@@ -1740,6 +1740,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "Zur Bestätigung {phrase} eingeben",
     "Turn off legacy protocols": "Ältere Mailprotokolle ausschalten",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "Ältere Mailprotokolle sind für Ihre Organisation ausgeschaltet. Nur {app} und JMAP-Apps können sich anmelden.",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Webmail-Knoten",
+    "Mail server node": "Mailserver-Knoten",
+    "{host} does not resolve": "{host} lässt sich nicht auflösen",
+    "unavailable": "nicht verfügbar",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "Einschätzung des Sprachmodells",
     "One of several signals the spam filter weighed": "Eines von mehreren Signalen, die der Spamfilter berücksichtigt hat",

web/src/locales/es.ts

@@ -1713,6 +1713,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "Para confirmar, escriba {phrase}",
     "Turn off legacy protocols": "Desactivar los protocolos de correo heredados",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "Los protocolos de correo heredados están desactivados para su organización. Solo {app} y las aplicaciones JMAP pueden iniciar sesión.",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Nodo del webmail",
+    "Mail server node": "Nodo del servidor de correo",
+    "{host} does not resolve": "{host} no se resuelve",
+    "unavailable": "no disponible",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "Opinión del modelo de lenguaje",
     "One of several signals the spam filter weighed": "Una de varias señales que el filtro de spam ha tenido en cuenta",

web/src/locales/fr.ts

@@ -1718,6 +1718,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "Pour confirmer, saisissez {phrase}",
     "Turn off legacy protocols": "Désactiver les protocoles de messagerie historiques",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "Les protocoles de messagerie historiques sont désactivés pour votre organisation. Seuls {app} et les applications JMAP peuvent se connecter.",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Nœud du webmail",
+    "Mail server node": "Nœud du serveur de messagerie",
+    "{host} does not resolve": "{host} ne se résout pas",
+    "unavailable": "indisponible",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "Avis du modèle de langage",
     "One of several signals the spam filter weighed": "Un signal parmi d'autres pris en compte par le filtre antispam",

web/src/locales/ja.ts

@@ -1721,6 +1721,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "確認のため {phrase} と入力してください",
     "Turn off legacy protocols": "従来のメールプロトコルをオフにする",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "組織では従来のメールプロトコルがオフになっています。サインインできるのは {app} と JMAP アプリのみです。",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Webメールのノード",
+    "Mail server node": "メールサーバーのノード",
+    "{host} does not resolve": "{host} の名前解決ができません",
+    "unavailable": "利用できません",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "言語モデルの見解",
     "One of several signals the spam filter weighed": "迷惑メールフィルターが考慮した複数の判断材料のひとつ",

web/src/locales/nl.ts

@@ -1710,6 +1710,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "Typ ter bevestiging {phrase}",
     "Turn off legacy protocols": "Verouderde mailprotocollen uitschakelen",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "Verouderde mailprotocollen zijn uitgeschakeld voor uw organisatie. Alleen {app} en JMAP-apps kunnen inloggen.",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Webmailnode",
+    "Mail server node": "Mailservernode",
+    "{host} does not resolve": "{host} wordt niet omgezet",
+    "unavailable": "niet beschikbaar",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "Oordeel van het taalmodel",
     "One of several signals the spam filter weighed": "Een van meerdere signalen die het spamfilter heeft meegewogen",

web/src/locales/pt-BR.ts

@@ -1716,6 +1716,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "Para confirmar, digite {phrase}",
     "Turn off legacy protocols": "Desativar os protocolos de e-mail legados",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "Os protocolos de e-mail legados estão desativados para sua organização. Só {app} e aplicativos JMAP podem entrar.",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Nó do webmail",
+    "Mail server node": "Nó do servidor de e-mail",
+    "{host} does not resolve": "{host} não resolve",
+    "unavailable": "indisponível",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "Opinião do modelo de linguagem",
     "One of several signals the spam filter weighed": "Um dos vários sinais considerados pelo filtro de spam",

web/src/locales/ru.ts

@@ -1715,6 +1715,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "Для подтверждения введите {phrase}",
     "Turn off legacy protocols": "Отключить устаревшие почтовые протоколы",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "Устаревшие почтовые протоколы отключены для вашей организации. Входить могут только {app} и приложения JMAP.",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Узел веб-почты",
+    "Mail server node": "Узел почтового сервера",
+    "{host} does not resolve": "{host} не разрешается",
+    "unavailable": "недоступно",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "Мнение языковой модели",
     "One of several signals the spam filter weighed": "Один из нескольких признаков, которые учёл спам-фильтр",

web/src/locales/uk.ts

@@ -1709,6 +1709,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "Для підтвердження введіть {phrase}",
     "Turn off legacy protocols": "Вимкнути застарілі поштові протоколи",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "Застарілі поштові протоколи вимкнено для вашої організації. Входити можуть лише {app} і програми JMAP.",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "Вузол вебпошти",
+    "Mail server node": "Вузол поштового сервера",
+    "{host} does not resolve": "{host} не розпізнається",
+    "unavailable": "недоступно",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "Думка мовної моделі",
     "One of several signals the spam filter weighed": "Одна з кількох ознак, які врахував спам-фільтр",

web/src/locales/zh-Hans.ts

@@ -1720,6 +1720,11 @@ export const catalog: Catalog = {
     "To confirm, type {phrase}": "请输入 {phrase} 以确认",
     "Turn off legacy protocols": "关闭传统邮件协议",
     "Legacy mail protocols are off for your organization. Only {app} and JMAP apps can sign in.": "您的组织已关闭传统邮件协议。只有 {app} 和 JMAP 应用可以登录。",
+    // ── About: webmail and mail server nodes (inbuxa) ──────────────
+    "Webmail node": "网页邮箱节点",
+    "Mail server node": "邮件服务器节点",
+    "{host} does not resolve": "无法解析 {host}",
+    "unavailable": "不可用",
     // ── Spam filter: the language model's opinion (inbuxa) ──────────
     "Language model's opinion": "语言模型的判断",
     "One of several signals the spam filter weighed": "垃圾邮件过滤考虑的多个信号之一",

web/src/views/settings/AboutSettings.tsx

@@ -1,15 +1,35 @@
+import { useEffect, useState } from "react";
 import { useSession } from "@/store/session";
 import { useAppName } from "@/lib/brand";
-import { client } from "@/jmap/client";
+import { apiFetch, client } from "@/jmap/client";
 import { APP_VERSION } from "@/lib/version";
 import { DEFAULT_SOURCE_URL } from "@/lib/source";
 import { withBase } from "@/lib/basePath";
 import { t, tNode } from "@/lib/i18n";
 import { InbuxaWordmark } from "@/ui/InbuxaWordmark";
 
+/** ihasmail-inbuxa: which webmail node answered and which mail node it talks to (server/src/nodes.ts). */
+interface Nodes {
+  webmail: string;
+  mailServer: { host: string; address: string | null; name: string | null };
+}
+
+function mailNodeLabel(m: Nodes["mailServer"]): string {
+  if (!m.address) return t("{host} does not resolve", { host: m.host });
+  return m.name ? `${m.name} (${m.address})` : m.address;
+}
+
 export function AboutSettings() {
   const appName = useAppName();
   const session = useSession((s) => s.session);
+  // Fetched on every visit, not cached with the session: when troubleshooting,
+  // the question is which nodes are in use now.
+  const [nodes, setNodes] = useState<Nodes | null | "error">(null);
+  useEffect(() => {
+    apiFetch<Nodes>("/api/about/nodes").then(setNodes).catch(() => setNodes("error"));
+  }, []);
+  const nodeCell = (v: (n: Nodes) => string) =>
+    nodes === null ? t("Loading…") : nodes === "error" ? t("unavailable") : <span className="mono notranslate" translate="no">{v(nodes)}</span>;
   const caps = Object.keys(session?.capabilities ?? {});
   // A deployment running modified code should offer its own source, not ours.
   const sourceUrl = session?.ihasmail?.sourceUrl ?? DEFAULT_SOURCE_URL;
@@ -36,6 +56,8 @@ export function AboutSettings() {
         <tbody>
           <tr><td>{t("Signed in as")}</td><td>{session?.username}</td></tr>
           <tr><td>{t("Mail server")}</td><td className="notranslate" translate="no">inbuxa</td></tr>
+          <tr><td>{t("Webmail node")}</td><td>{nodeCell((n) => n.webmail)}</td></tr>
+          <tr><td>{t("Mail server node")}</td><td>{nodeCell((n) => mailNodeLabel(n.mailServer))}</td></tr>
           <tr><td>{t("Accounts")}</td><td>{Object.values(session?.accounts ?? {}).map((a) => a.name).join(", ")}</td></tr>
           <tr><td>{t("Max upload")}</td><td>{t("{size} MB", { size: Math.round(client.maxSizeUpload / 1048576) })}</td></tr>
           <tr><td>{t("Image privacy proxy")}</td><td>{session?.ihasmail?.imageProxy ? t("enabled") : t("disabled")}</td></tr>