NobMail

diff --git a/data/Dockerfiles/acme/acme.sh b/data/Dockerfiles/acme/acme.sh
index 69b18bc1..2aab8e7e 100755
--- a/data/Dockerfiles/acme/acme.sh
+++ b/data/Dockerfiles/acme/acme.sh
@@ -246,6 +246,25 @@ while true; do
     done
     VALIDATED_CONFIG_DOMAINS+=("${VALIDATED_CONFIG_DOMAINS_SUBDOMAINS[*]}")
   done
+
+  # Fetch alias domains where target domain has MTA-STS enabled
+  if [[ ${AUTODISCOVER_SAN} == "y" ]]; then
+    SQL_ALIAS_DOMAINS=$(mariadb --skip-ssl --socket=/var/run/mysqld/mysqld.sock -u ${DBUSER} -p${DBPASS} ${DBNAME} -e "SELECT ad.alias_domain FROM alias_domain ad INNER JOIN mta_sts m ON ad.target_domain = m.domain WHERE ad.active = 1 AND m.active = 1" -Bs)
+    if [[ $? -eq 0 ]]; then
+      while read alias_domain; do
+        if [[ -z "${alias_domain}" ]]; then
+          # ignore empty lines
+          continue
+        fi
+        # Only add mta-sts subdomain for alias domains
+        if [[ "mta-sts.${alias_domain}" != "${MAILCOW_HOSTNAME}" ]]; then
+          if check_domain "mta-sts.${alias_domain}"; then
+            VALIDATED_CONFIG_DOMAINS+=("mta-sts.${alias_domain}")
+          fi
+        fi
+      done <<< "${SQL_ALIAS_DOMAINS}"
+    fi
+  fi
   fi
 
   if check_domain ${MAILCOW_HOSTNAME}; then
diff --git a/data/web/inc/ajax/dns_diagnostics.php b/data/web/inc/ajax/dns_diagnostics.php
index b48239e1..95e34e88 100644
--- a/data/web/inc/ajax/dns_diagnostics.php
+++ b/data/web/inc/ajax/dns_diagnostics.php
@@ -129,7 +129,16 @@ if (isset($_SESSION['mailcow_cc_role']) && ($_SESSION['mailcow_cc_role'] == "adm
     );
   }
 
-  $mta_sts = mailbox('get', 'mta_sts', $domain);
+  // Check if domain is an alias domain and get target domain's MTA-STS
+  $alias_domain_details = mailbox('get', 'alias_domain_details', $domain);
+  $mta_sts_domain = $domain;
+  
+  if ($alias_domain_details !== false && !empty($alias_domain_details['target_domain'])) {
+    // This is an alias domain, check target domain for MTA-STS
+    $mta_sts_domain = $alias_domain_details['target_domain'];
+  }
+  
+  $mta_sts = mailbox('get', 'mta_sts', $mta_sts_domain);
   if (count($mta_sts) > 0 && $mta_sts['active'] == 1) {
     if (!in_array($domain, $alias_domains)) {
       $records[] = array(
diff --git a/data/web/mta-sts.php b/data/web/mta-sts.php
index 650b8b58..0c6f1a24 100644
--- a/data/web/mta-sts.php
+++ b/data/web/mta-sts.php
@@ -7,7 +7,30 @@ if (!isset($_SERVER['HTTP_HOST']) || strpos($_SERVER['HTTP_HOST'], 'mta-sts.') !
 }
 
 $host = preg_replace('/:[0-9]+$/', '', $_SERVER['HTTP_HOST']);
-$domain = str_replace('mta-sts.', '', $host);
+$domain = idn_to_ascii(strtolower(str_replace('mta-sts.', '', $host)), 0, INTL_IDNA_VARIANT_UTS46);
+
+// Validate domain or return 404 on error
+if ($domain === false || empty($domain)) {
+  http_response_code(404);
+  exit;
+}
+
+// Check if domain is an alias domain and resolve to target domain
+try {
+  $stmt = $pdo->prepare("SELECT `target_domain` FROM `alias_domain` WHERE `alias_domain` = :domain");
+  $stmt->execute(array(':domain' => $domain));
+  $alias_row = $stmt->fetch(PDO::FETCH_ASSOC);
+  
+  if ($alias_row !== false && !empty($alias_row['target_domain'])) {
+    // This is an alias domain, use the target domain for MTA-STS lookup
+    $domain = $alias_row['target_domain'];
+  }
+} catch (PDOException $e) {
+  // On database error, return 404
+  http_response_code(404);
+  exit;
+}
+
 $mta_sts = mailbox('get', 'mta_sts', $domain);
 
 if (count($mta_sts) == 0 ||
diff --git a/docker-compose.yml b/docker-compose.yml
index fccd9ee4..f09afca2 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -465,7 +465,7 @@ services:
           condition: service_started
         unbound-mailcow:
           condition: service_healthy
-      image: ghcr.io/mailcow/acme:1.94
+      image: ghcr.io/mailcow/acme:1.95
       dns:
         - ${IPV4_NETWORK:-172.22.1}.254
       environment: