src/features/certificates/CertificateSetupPage.tsx

@@ -41,6 +41,8 @@ interface DomainRow {
   name: string;
   automatic: boolean;
   providerId?: string;
+  /** The domain's own certificate hostnames, kept as they are when it's switched. */
+  hostnames: string[];
   dnsAutomatic: boolean;
   zone: ReturnType<typeof parseZone>;
 }
@@ -93,6 +95,7 @@ async function load(): Promise<Loaded> {
           name: String(d.name),
           automatic: cm['@type'] === 'Automatic',
           providerId: cm.acmeProviderId as string | undefined,
+          hostnames: cm['@type'] === 'Automatic' ? keys(cm.subjectAlternativeNames) : [],
           dnsAutomatic: dm['@type'] === 'Automatic',
           zone: parseZone(d.dnsZoneFile as string | undefined),
         };
@@ -113,6 +116,9 @@ async function load(): Promise<Loaded> {
   };
 }
 
+/** "a and b" for the default pair, "a, b, c" for a domain's own list. */
+const joinNames = (names: string[]) => (names.length === 2 ? names.join(' and ') : names.join(', '));
+
 /** When the switch happened, read in the click handler, for telling a new certificate from an old one. */
 async function switchedAt(): Promise<number> {
   return Date.now();
@@ -206,7 +212,7 @@ export function CertificateSetupPage() {
   const chosen = useMemo(() => (data ? data.domains.filter((d) => picked.has(d.id)) : []), [data, picked]);
   const methodOf = (d: DomainRow): Method => (d.dnsAutomatic ? 'dns' : 'tls');
   const namesOf = useCallback(
-    (d: DomainRow) => orderNames(d.name, methodOf(d), data?.serverName ?? '', d.zone),
+    (d: DomainRow) => orderNames(d.name, methodOf(d), data?.serverName ?? '', d.zone, d.hostnames),
     [data],
   );
 
@@ -344,7 +350,7 @@ export function CertificateSetupPage() {
             certificateManagement: {
               '@type': 'Automatic',
               acmeProviderId: ids[methodOf(d)],
-              subjectAlternativeNames: {},
+              subjectAlternativeNames: Object.fromEntries(d.hostnames.map((h) => [h, true])),
             },
           },
         ]),
@@ -506,7 +512,7 @@ export function CertificateSetupPage() {
               <CheckCircle2 className="h-4 w-4 text-emerald-600" />
               {t('certSetup.dnsReady', '{{domain}}: checked through its connected DNS, covering {{names}}.', {
                 domain: d.name,
-                names: namesOf(d).join(' and '),
+                names: joinNames(namesOf(d)),
               })}
             </p>
           ))}

src/features/certificates/names.test.ts

@@ -27,6 +27,13 @@ describe('orderNames', () => {
     ]);
   });
 
+  it("uses a domain's own hostnames in place of the defaults, with either method", () => {
+    const own = ['mail', 'Example.com', 'smtp.example.com', 'mail'];
+    const want = ['mail.example.com', 'example.com', 'smtp.example.com'];
+    expect(orderNames('example.com', 'dns', 'mail.example.com', [], own)).toEqual(want);
+    expect(orderNames('example.com', 'tls', 'mail.example.com', [], own)).toEqual(want);
+  });
+
   it('leaves out a server name in another domain', () => {
     expect(orderNames('example.com', 'tls', 'mail.other.net')).not.toContain('mail.other.net');
   });

src/features/certificates/names.ts

@@ -11,8 +11,10 @@
  * The server decides the names (common/src/network/acme/order.rs): with DNS
  * validation it asks for the domain and a wildcard under it; otherwise for
  * mta-sts, ua-auto-config, autoconfig and autodiscover under the domain, plus
- * the server's own name when it's inside the domain. Every name must pass, or
- * the whole order fails and keeps retrying, so the guide checks them first.
+ * the server's own name when it's inside the domain. A domain's own hostname
+ * list replaces all of that: a name without a dot gets the domain added, one
+ * with a dot is used as written. Every name must pass, or the whole order
+ * fails and keeps retrying, so the guide checks them first.
  */
 
 import type { ZoneRecord } from '@/features/dns/zone';
@@ -25,8 +27,17 @@ function inZone(name: string, domain: string): boolean {
   return name === domain || name.endsWith(`.${domain}`);
 }
 
-export function orderNames(domain: string, method: Method, serverName: string, zone: ZoneRecord[] = []): string[] {
+export function orderNames(
+  domain: string,
+  method: Method,
+  serverName: string,
+  zone: ZoneRecord[] = [],
+  hostnames: string[] = [],
+): string[] {
   const d = domain.toLowerCase();
+  if (hostnames.length > 0) {
+    return [...new Set(hostnames.map((h) => (h.includes('.') ? h : `${h}.${d}`).toLowerCase()))];
+  }
   if (method === 'dns') return [`*.${d}`, d];
   const names = new Set(TECHNICAL_NAMES.map((h) => `${h}.${d}`));
   const host = serverName.toLowerCase().replace(/\.$/, '');