diff --git a/deploy/nginx/deploy_certificate.py b/deploy/nginx/deploy_certificate.py
index 83a7b55..c335901 100644
--- a/deploy/nginx/deploy_certificate.py
+++ b/deploy/nginx/deploy_certificate.py
@@ -17,7 +17,10 @@ import time
 import uuid
 
 
-DOMAINS = ('solit.cn', 'mail.solit.cn', 'smtp.solit.cn', 'imap.solit.cn', 'pop.solit.cn')
+DOMAINS = ('solit.cn', '*.solit.cn')
+VERIFY_HOSTNAMES = ('solit.cn', 'web.solit.cn', 'mail.solit.cn', 'smtp.solit.cn',
+                    'imap.solit.cn', 'pop.solit.cn')
+CERTIFICATE_SNI = 'web.solit.cn'
 LINEAGE = Path('/var/lib/smail-acme-tls/certificates')
 TARGET = Path('/opt/smail/ssl')
 BACKUPS = Path('/var/backups')
@@ -96,7 +99,13 @@ def replace_file(path, data, uid, gid):
 
 
 def validate(directory):
-    for domain in DOMAINS:
+    names = run('openssl', 'x509', '-in', str(directory / 'candidate.crt'), '-noout',
+                '-ext', 'subjectAltName').decode('utf-8')
+    certificate_domains = {item.strip()[4:] for line in names.splitlines()
+                           for item in line.split(',') if item.strip().startswith('DNS:')}
+    if not set(DOMAINS).issubset(certificate_domains):
+        raise RuntimeError('证书必须同时覆盖根域名和泛域名')
+    for domain in VERIFY_HOSTNAMES:
         run('openssl', 'verify', '-CAfile', CA_FILE, '-purpose', 'sslserver',
             '-untrusted', str(directory / 'candidate.issuer.crt'), '-verify_hostname', domain,
             str(directory / 'candidate.crt'))
@@ -119,7 +128,7 @@ def verify_live_certificate(fingerprint):
         while True:
             try:
                 with socket.create_connection(('127.0.0.1', port), timeout=2) as connection:
-                    with context.wrap_socket(connection, server_hostname='mail.solit.cn') as secure:
+                    with context.wrap_socket(connection, server_hostname=CERTIFICATE_SNI) as secure:
                         actual = hashlib.sha256(secure.getpeercert(binary_form=True)).hexdigest()
                 if actual == fingerprint:
                     break
diff --git a/deploy/nginx/renew_certificate.py b/deploy/nginx/renew_certificate.py
index 8d05444..f036560 100644
--- a/deploy/nginx/renew_certificate.py
+++ b/deploy/nginx/renew_certificate.py
@@ -11,7 +11,7 @@ import deploy_certificate as deploy
 
 
 ROOT = Path('/var/lib/smail-acme-tls')
-DOMAINS = ('solit.cn', 'mail.solit.cn', 'smtp.solit.cn', 'imap.solit.cn', 'pop.solit.cn')
+DOMAINS = deploy.DOMAINS
 RENEW_TIMEOUT = 600
 WEBROOT = Path('/var/lib/smail-acme')
 
diff --git a/deploy/nginx/smail.conf b/deploy/nginx/smail.conf
index ec1deb9..3af7164 100644
--- a/deploy/nginx/smail.conf
+++ b/deploy/nginx/smail.conf
@@ -8,7 +8,7 @@ server {
 server {
     listen 80;
     listen [::]:80;
-    server_name solit.cn mail.solit.cn smtp.solit.cn imap.solit.cn pop.solit.cn;
+    server_name solit.cn mail.solit.cn web.solit.cn smtp.solit.cn imap.solit.cn pop.solit.cn;
 
     location ^~ /.well-known/acme-challenge/ {
         root /var/lib/smail-acme;
@@ -17,7 +17,7 @@ server {
     }
 
     location / {
-        return 308 https://mail.solit.cn$request_uri;
+        return 308 https://web.solit.cn$request_uri;
     }
 }
 
@@ -31,16 +31,16 @@ server {
 server {
     listen 443 ssl;
     listen [::]:443 ssl;
-    server_name solit.cn smtp.solit.cn imap.solit.cn pop.solit.cn;
+    server_name solit.cn mail.solit.cn smtp.solit.cn imap.solit.cn pop.solit.cn;
     ssl_certificate /opt/smail/ssl/custom.crt;
     ssl_certificate_key /opt/smail/ssl/custom.key;
-    return 308 https://mail.solit.cn$request_uri;
+    return 308 https://web.solit.cn$request_uri;
 }
 
 server {
     listen 443 ssl;
     listen [::]:443 ssl;
-    server_name mail.solit.cn;
+    server_name web.solit.cn;
     ssl_certificate /opt/smail/ssl/custom.crt;
     ssl_certificate_key /opt/smail/ssl/custom.key;
 
@@ -50,10 +50,11 @@ server {
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $remote_addr;
+        proxy_set_header X-Forwarded-Host $host;
         proxy_set_header X-Forwarded-Proto https;
         proxy_set_header Connection "";
         proxy_ssl_server_name on;
-        proxy_ssl_name mail.solit.cn;
+        proxy_ssl_name web.solit.cn;
         proxy_ssl_verify on;
         proxy_ssl_verify_depth 3;
         proxy_ssl_trusted_certificate /etc/ssl/certs/ca-certificates.crt;
diff --git a/test/deployment/test_certificate_renewal.py b/test/deployment/test_certificate_renewal.py
index 76d9823..6162af4 100644
--- a/test/deployment/test_certificate_renewal.py
+++ b/test/deployment/test_certificate_renewal.py
@@ -264,7 +264,7 @@ class DeploymentTests(unittest.TestCase):
 
     def test_wrong_domain_does_not_change_live_files(self):
         with patch.object(deploy, 'DOMAINS', ('wrong.example',)), \
-                self.assertRaises(subprocess.CalledProcessError):
+                self.assertRaisesRegex(RuntimeError, '根域名和泛域名'):
             deploy.main()
         self.assert_old_untouched()
 
diff --git a/test/deployment/test_domain_acceptance.py b/test/deployment/test_domain_acceptance.py
new file mode 100644
index 0000000..69657d9
--- /dev/null
+++ b/test/deployment/test_domain_acceptance.py
@@ -0,0 +1,28 @@
+"""验证 Smail 的后台域名、别名跳转和根域名泛域名证书约束。"""
+
+from pathlib import Path
+import unittest
+
+
+ROOT = Path(__file__).resolve().parents[2]
+NGINX = (ROOT / 'deploy/nginx/smail.conf').read_text(encoding='utf-8')
+CERTIFICATE = (ROOT / 'deploy/nginx/deploy_certificate.py').read_text(encoding='utf-8')
+RENEWAL = (ROOT / 'deploy/nginx/renew_certificate.py').read_text(encoding='utf-8')
+
+
+class DomainAcceptanceTest(unittest.TestCase):
+    def test_web_domain_is_the_only_public_web_proxy(self):
+        self.assertIn('server_name web.solit.cn;', NGINX)
+        self.assertIn('proxy_ssl_name web.solit.cn;', NGINX)
+        self.assertIn('return 308 https://web.solit.cn$request_uri;', NGINX)
+        self.assertNotIn('return 308 https://mail.solit.cn$request_uri;', NGINX)
+
+    def test_certificate_requests_root_and_wildcard(self):
+        self.assertIn("DOMAINS = ('solit.cn', '*.solit.cn')", CERTIFICATE)
+        self.assertIn("CERTIFICATE_SNI = 'web.solit.cn'", CERTIFICATE)
+        self.assertIn("'web.solit.cn'", CERTIFICATE)
+        self.assertIn('DOMAINS = deploy.DOMAINS', RENEWAL)
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)
diff --git a/test/deployment/test_nginx_redirect_acceptance.py b/test/deployment/test_nginx_redirect_acceptance.py
index ba4715d..7517790 100644
--- a/test/deployment/test_nginx_redirect_acceptance.py
+++ b/test/deployment/test_nginx_redirect_acceptance.py
@@ -11,7 +11,7 @@ import verify_nginx_tls as verify
 
 
 class RedirectAcceptanceTest(unittest.TestCase):
-    expected = 'https://mail.solit.cn/acceptance?x=1'
+    expected = 'https://web.solit.cn/acceptance?x=1'
 
     def check(self, first, second):
         results = {'checks': []}
@@ -29,12 +29,12 @@ class RedirectAcceptanceTest(unittest.TestCase):
         self.assertEqual(self.check(self.response(), self.response()), [])
 
     def test_internal_https_port_is_failure(self):
-        failures = self.check(self.response(), self.response('https://mail.solit.cn:8002/acceptance?x=1'))
+        failures = self.check(self.response(), self.response('https://web.solit.cn:8002/acceptance?x=1'))
         self.assertEqual(len(failures), 1)
         self.assertEqual(failures[0]['port'], 8001)
 
     def test_public_port_does_not_skip_validation(self):
-        failures = self.check(self.response('http://mail.solit.cn/acceptance?x=1'), self.response())
+        failures = self.check(self.response('http://web.solit.cn/acceptance?x=1'), self.response())
         self.assertEqual([item['port'] for item in failures], [80])
 
     def test_missing_location_records_failure(self):
@@ -46,7 +46,7 @@ class RedirectAcceptanceTest(unittest.TestCase):
         self.assertEqual(failures[0]['actualStatus'], 200)
 
     def test_path_and_query_must_be_preserved(self):
-        for location in ('https://mail.solit.cn/', 'https://mail.solit.cn/acceptance',
+        for location in ('https://web.solit.cn/', 'https://web.solit.cn/acceptance',
                          'https://other.invalid/acceptance?x=1'):
             with self.subTest(location=location):
                 self.assertTrue(self.check(self.response(), self.response(location)))
diff --git a/test/deployment/verify_nginx_tls.py b/test/deployment/verify_nginx_tls.py
index f743768..1e2feab 100644
--- a/test/deployment/verify_nginx_tls.py
+++ b/test/deployment/verify_nginx_tls.py
@@ -11,7 +11,7 @@ import ssl
 import subprocess
 
 
-HOST = 'mail.solit.cn'
+HOST = 'web.solit.cn'
 CONTEXT = ssl.create_default_context()
 
 
@@ -47,7 +47,8 @@ def main():
     leaf = subprocess.run(['openssl', 'x509', '-in', '/opt/smail/ssl/custom.crt', '-outform', 'DER'],
                           check=True, capture_output=True).stdout
     expected = hashlib.sha256(leaf).hexdigest()
-    for port, host in [(443, HOST), (8002, HOST), (465, 'smtp.solit.cn'),
+    for port, host in [(443, HOST), (443, 'solit.cn'), (443, 'mail.solit.cn'),
+                       (8002, HOST), (465, 'smtp.solit.cn'),
                        (993, 'imap.solit.cn'), (995, 'pop.solit.cn')]:
         with socket.create_connection(('127.0.0.1', port), timeout=10) as raw:
             with CONTEXT.wrap_socket(raw, server_hostname=host) as stream:
@@ -86,7 +87,7 @@ def main():
         raise AssertionError('unknown SNI accepted')
     root = json.loads(Path('/opt/smail/config/config.json').read_text())
     assert root['http']['port'] == 8001 and root['http']['httpsPort'] == 8002
-    assert root['security']['webAuthnRpOrigins'] == ['https://mail.solit.cn']
+    assert root['security']['webAuthnRpOrigins'] == ['https://web.solit.cn']
     results['fingerprintSHA256'] = expected
     results['status'] = 'failed' if results['failures'] else 'passed'
     print(json.dumps(results, ensure_ascii=False, indent=2))