diff --git a/data/web/inc/header.inc.php b/data/web/inc/header.inc.php
index 533711de..8e5b6d07 100644
--- a/data/web/inc/header.inc.php
+++ b/data/web/inc/header.inc.php
@@ -77,6 +77,11 @@
                 <li<?= (preg_match("/mailbox/i", $_SERVER['REQUEST_URI'])) ? ' class="active"' : ''; ?>><a href="/mailbox.php"><?= $lang['header']['mailboxes']; ?></a></li>
               <?php
               }
+              if ($_SESSION['mailcow_cc_role'] == 'admin') {
+              ?>
+                <li<?= (preg_match("/diagnostics/i", $_SERVER['REQUEST_URI'])) ? ' class="active"' : ''; ?>><a href="/diagnostics.php"><?= $lang['header']['diagnostics']; ?></a></li>
+              <?php
+              }
               if ($_SESSION['mailcow_cc_role'] != 'admin') {
               ?>
                 <li<?= (preg_match("/user/i", $_SERVER['REQUEST_URI'])) ? ' class="active"' : ''; ?>><a href="/user.php"><?= $lang['header']['user_settings']; ?></a></li>
diff --git a/data/web/lang/lang.de.php b/data/web/lang/lang.de.php
index eef13b3f..732171cc 100644
--- a/data/web/lang/lang.de.php
+++ b/data/web/lang/lang.de.php
@@ -214,6 +214,7 @@ $lang['header']['mailcow_settings'] = 'Konfiguration';
 $lang['header']['administration'] = 'Administration';
 $lang['header']['mailboxes'] = 'Mailboxen';
 $lang['header']['user_settings'] = 'Benutzereinstellungen';
+$lang['header']['diagnostics'] = 'Diagnose';
 $lang['header']['login'] = 'Anmeldung';
 $lang['header']['logged_in_as_logout'] = 'Eingeloggt als <b>%s</b> (abmelden)';
 $lang['header']['logged_in_as_logout_dual'] = 'Eingeloggt als <b>%s <span class="text-info">[%s]</span></b>';
@@ -495,3 +496,9 @@ $lang['admin']['add_forwarding_host'] = 'Weiterleitungs-Host hinzufügen';
 $lang['delete']['remove_forwardinghost_warning'] = '<b>Warnung:</b> Sie entfernen den Weiterleitungs-Host <b>%s</b>!';
 $lang['success']['forwarding_host_removed'] = "Weiterleitungs-Host %s wurde entfernt";
 $lang['success']['forwarding_host_added'] = "Weiterleitungs-Host %s wurde hinzugefügt";
+$lang['diagnostics']['dns_records'] = 'DNS-Einträge';
+$lang['diagnostics']['dns_records_24hours'] = 'Bitte beachten Sie, dass es bis zu 24 Stunden dauern kann, bis Änderungen an Ihren DNS-Einträgen als aktueller Status auf dieser Seite dargestellt werden. Diese Seite ist nur als Hilfsmittel gedacht, um die korrekten Werte für DNS-Einträge zu anzuzeigen und zu überprüfen, ob die Daten im DNS hinterlegt sind.';
+$lang['diagnostics']['dns_records_name'] = 'Name';
+$lang['diagnostics']['dns_records_type'] = 'Typ';
+$lang['diagnostics']['dns_records_data'] = 'Korrekte Daten';
+$lang['diagnostics']['dns_records_status'] = 'Aktueller Status';
diff --git a/data/web/lang/lang.en.php b/data/web/lang/lang.en.php
index 3be72fec..391c7d01 100644
--- a/data/web/lang/lang.en.php
+++ b/data/web/lang/lang.en.php
@@ -216,6 +216,7 @@ $lang['header']['mailcow_settings'] = 'Configuration';
 $lang['header']['administration'] = 'Administration';
 $lang['header']['mailboxes'] = 'Mailboxes';
 $lang['header']['user_settings'] = 'User settings';
+$lang['header']['diagnostics'] = 'Diagnostics';
 $lang['header']['login'] = 'Login';
 $lang['header']['logged_in_as_logout'] = 'Logged in as <b>%s</b> (logout)';
 $lang['header']['logged_in_as_logout_dual'] = 'Logged in as <b>%s <span class="text-info">[%s]</span></b>';
@@ -508,3 +509,9 @@ $lang['admin']['add_forwarding_host'] = 'Add Forwarding Host';
 $lang['delete']['remove_forwardinghost_warning'] = '<b>Warning:</b> You are about to remove the forwarding host <b>%s</b>!';
 $lang['success']['forwarding_host_removed'] = "Forwarding host %s has been removed";
 $lang['success']['forwarding_host_added'] = "Forwarding host %s has been added";
+$lang['diagnostics']['dns_records'] = 'DNS Records';
+$lang['diagnostics']['dns_records_24hours'] = 'Please note that changes made to DNS may take up to 24 hours to correctly have their current state reflected on this page. It is intended as a way for you to easily see how to configure your DNS records and to check whether all your records are correctly stored in DNS.';
+$lang['diagnostics']['dns_records_name'] = 'Name';
+$lang['diagnostics']['dns_records_type'] = 'Type';
+$lang['diagnostics']['dns_records_data'] = 'Correct Data';
+$lang['diagnostics']['dns_records_status'] = 'Current State';
diff --git a/diagnostics.php b/diagnostics.php
new file mode 100644
index 00000000..4de0082e
--- /dev/null
+++ b/diagnostics.php
@@ -0,0 +1,272 @@
+<?php
+require_once 'inc/prerequisites.inc.php';
+require_once 'inc/spf.inc.php';
+
+function in_net($addr, $net) {
+  $net = explode('/', $net);
+  if (count($net) > 1) {
+    $mask = $net[1];
+  }
+  $net = inet_pton($net[0]);
+  $addr = inet_pton($addr);
+  $length = strlen($net); // 4 for IPv4, 16 for IPv6
+  if (strlen($net) != strlen($addr)) {
+    return false;
+  }
+  if (!isset($mask)) {
+    $mask = $length * 8;
+  }
+  $addr_bin = '';
+  $net_bin = '';
+  for ($i = 0; $i < $length; ++$i) {
+    $addr_bin .= str_pad(decbin(ord(substr($addr, $i, $i+1))), 8, '0', STR_PAD_LEFT);
+    $net_bin .= str_pad(decbin(ord(substr($net, $i, $i+1))), 8, '0', STR_PAD_LEFT);
+  }
+  return substr($addr_bin, 0, $mask) == substr($net_bin, 0, $mask);
+}
+
+if (isset($_SESSION['mailcow_cc_role']) && $_SESSION['mailcow_cc_role'] == "admin") {
+require_once("inc/header.inc.php");
+
+$ch = curl_init('http://ipv4.mailcow.email');
+curl_setopt($ch, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);
+curl_setopt($ch, CURLOPT_VERBOSE, false);
+curl_setopt($ch, CURLOPT_HEADER, false);
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
+curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 3);
+$ip = curl_exec($ch);
+curl_close($ch);
+
+$ch = curl_init('http://ipv6.mailcow.email');
+curl_setopt($ch, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V6);
+curl_setopt($ch, CURLOPT_VERBOSE, false);
+curl_setopt($ch, CURLOPT_HEADER, false);
+curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
+curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 3);
+$ip6 = curl_exec($ch);
+curl_close($ch);
+
+$ptr = implode('.', array_reverse(explode('.', $ip))) . '.in-addr.arpa';
+if (!empty($ip6)) {
+  $ip6_full = str_replace('::', str_repeat(':', 9-substr_count($ip6, ':')), $ip6);
+  $ip6_full = str_replace('::', ':0:', $ip6_full);
+  $ip6_full = str_replace('::', ':0:', $ip6_full);
+  $ptr6 = '';
+  foreach (explode(':', $ip6_full) as $part) {
+    $ptr6 .= str_pad($part, 4, '0', STR_PAD_LEFT);
+  }
+  $ptr6 = implode('.', array_reverse(str_split($ptr6, 1))) . '.ip6.arpa';
+}
+
+$https_port = strpos($_SERVER['HTTP_HOST'], ':');
+if ($https_port === FALSE) {
+  $https_port = 443;
+} else {
+  $https_port = substr($_SERVER['HTTP_HOST'], $https_port+1);
+}
+
+$records = array();
+$records[] = array($mailcow_hostname, 'A', $ip);
+$records[] = array($ptr, 'PTR', $mailcow_hostname);
+if (!empty($ip6)) {
+  $records[] = array($mailcow_hostname, 'AAAA', $ip6);
+  $records[] = array($ptr6, 'PTR', $mailcow_hostname);
+}
+$domains = mailbox('get', 'domains');
+foreach(mailbox('get', 'domains') as $domain) {
+  $domains = array_merge($domains, mailbox('get', 'alias_domains', $domain));
+}
+
+if (!isset($autodiscover_config['sieve'])) {
+  $autodiscover_config['sieve'] = array('server' => $mailcow_hostname, 'port' => array_pop(explode(':', getenv('SIEVE_PORT'))));
+}
+
+$records[] = array('_25._tcp.'                                              . $autodiscover_config['smtp']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['smtp']['server'], 25, 1));
+$records[] = array('_' . $https_port    . '._tcp.' . $mailcow_hostname, 'TLSA', generate_tlsa_digest($mailcow_hostname, $https_port));
+$records[] = array('_' . $autodiscover_config['pop3']['tlsport'] . '._tcp.' . $autodiscover_config['pop3']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['pop3']['server'], $autodiscover_config['pop3']['tlsport'], 1));
+$records[] = array('_' . $autodiscover_config['imap']['tlsport'] . '._tcp.' . $autodiscover_config['imap']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['imap']['server'], $autodiscover_config['imap']['tlsport'], 1));
+$records[] = array('_' . $autodiscover_config['smtp']['port']    . '._tcp.' . $autodiscover_config['smtp']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['smtp']['server'], $autodiscover_config['smtp']['port']));
+$records[] = array('_' . $autodiscover_config['smtp']['tlsport'] . '._tcp.' . $autodiscover_config['smtp']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['smtp']['server'], $autodiscover_config['smtp']['tlsport'], 1));
+$records[] = array('_' . $autodiscover_config['imap']['port']    . '._tcp.' . $autodiscover_config['imap']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['imap']['server'], $autodiscover_config['imap']['port']));
+$records[] = array('_' . $autodiscover_config['pop3']['port']    . '._tcp.' . $autodiscover_config['pop3']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['pop3']['server'], $autodiscover_config['pop3']['port']));
+$records[] = array('_' . $autodiscover_config['sieve']['port']   . '._tcp.' . $autodiscover_config['sieve']['server'], 'TLSA', generate_tlsa_digest($autodiscover_config['sieve']['server'], $autodiscover_config['sieve']['port'], 1));
+
+foreach ($domains as $domain) {
+  $records[] = array($domain, 'MX', $mailcow_hostname);
+  $records[] = array('autodiscover.' . $domain, 'CNAME', $mailcow_hostname);
+  $records[] = array('_autodiscover._tcp.' . $domain, 'SRV', $mailcow_hostname . ' ' . $https_port);
+  $records[] = array('autoconfig.' . $domain, 'CNAME', $mailcow_hostname);
+  $records[] = array($domain, 'TXT', 'v=spf1 mx -all');
+  $records[] = array('_dmarc.' . $domain, 'TXT', 'v=DMARC1; p=reject', 'v=DMARC1; p=');
+  
+  if (!empty($dkim = dkim('details', $domain))) {
+    $records[] = array($dkim['dkim_selector'] . '._domainkey.' . $domain, 'TXT', $dkim['dkim_txt']);
+  }
+
+  $current_records = dns_get_record('_pop3._tcp.' . $domain, DNS_SRV);
+  if (count($current_records) == 0 || $current_records[0]['target'] != '') {
+    if ($autodiscover_config['pop3']['tlsport'] != '110')  {
+      $records[] = array('_pop3._tcp.' . $domain, 'SRV', $autodiscover_config['pop3']['server'] . ' ' . $autodiscover_config['pop3']['tlsport']);
+    }
+  } else {
+      $records[] = array('_pop3._tcp.' . $domain, 'SRV', '. 0');
+  }
+  $current_records = dns_get_record('_pop3s._tcp.' . $domain, DNS_SRV);
+  if (count($current_records) == 0 || $current_records[0]['target'] != '') {
+    if ($autodiscover_config['pop3']['port'] != '995')  {
+      $records[] = array('_pop3s._tcp.' . $domain, 'SRV', $autodiscover_config['pop3']['server'] . ' ' . $autodiscover_config['pop3']['port']);
+    }
+  } else {
+      $records[] = array('_pop3s._tcp.' . $domain, 'SRV', '. 0');
+  }
+  if ($autodiscover_config['imap']['tlsport'] != '143')  {
+    $records[] = array('_imap._tcp.' . $domain, 'SRV', $autodiscover_config['imap']['server'] . ' ' . $autodiscover_config['imap']['tlsport']);
+  }
+  if ($autodiscover_config['imap']['port'] != '993')  {
+    $records[] = array('_imaps._tcp.' . $domain, 'SRV', $autodiscover_config['imap']['server'] . ' ' . $autodiscover_config['imap']['port']);
+  }
+  if ($autodiscover_config['smtp']['tlsport'] != '587')  {
+    $records[] = array('_submission._tcp.' . $domain, 'SRV', $autodiscover_config['smtp']['server'] . ' ' . $autodiscover_config['smtp']['tlsport']);
+  }
+  if ($autodiscover_config['smtp']['port'] != '465')  {
+    $records[] = array('_smtps._tcp.' . $domain, 'SRV', $autodiscover_config['smtp']['server'] . ' ' . $autodiscover_config['smtp']['port']);
+  }
+  if ($autodiscover_config['sieve']['port'] != '4190')  {
+    $records[] = array('_sieve._tcp.' . $domain, 'SRV', $autodiscover_config['sieve']['server'] . ' ' . $autodiscover_config['sieve']['port']);
+  }
+}
+
+define('state_good',  "&#10003;");
+define('state_missing',   "&#x2717;");
+define('state_nomatch', "?");
+
+$record_types = array(
+  'A' => DNS_A,
+  'AAAA' => DNS_AAAA,
+  'CNAME' => DNS_CNAME,
+  'MX' => DNS_MX,
+  'PTR' => DNS_PTR,
+  'SRV' => DNS_SRV,
+  'TXT' => DNS_TXT,
+);
+$data_field = array(
+  'A' => 'ip',
+  'AAAA' => 'ipv6',
+  'CNAME' => 'target',
+  'MX' => 'target',
+  'PTR' => 'target',
+  'SRV' => 'data',
+  'TLSA' => 'data',
+  'TXT' => 'txt',
+);
+?>
+<div class="container">
+  <h3><?=$lang['diagnostics']['dns_records'];?></h3>
+  <p><?=$lang['diagnostics']['dns_records_24hours'];?></p>
+  <div class="table-responsive" id="dnstable">
+    <table class="table table-striped">
+      <tr> <th><?=$lang['diagnostics']['dns_records_name'];?></th> <th><?=$lang['diagnostics']['dns_records_type'];?></th> <th><?=$lang['diagnostics']['dns_records_data'];?></th ><th><?=$lang['diagnostics']['dns_records_status'];?></th> </tr>
+<?php
+foreach ($records as $record)
+{
+  $record[1] = strtoupper($record[1]);
+  $state = state_missing;
+  if ($record[1] == 'TLSA') {
+    $currents = dns_get_record($record[0], 52, $_, $_, TRUE);
+    foreach ($currents as &$current) {
+      $current['type'] = 'TLSA';
+      $current['cert_usage'] = hexdec(bin2hex($current['data']{0}));
+      $current['selector'] = hexdec(bin2hex($current['data']{1}));
+      $current['match_type'] = hexdec(bin2hex($current['data']{2}));
+      $current['cert_data'] = bin2hex(substr($current['data'], 3));
+      $current['data'] = $current['cert_usage'] . ' ' . $current['selector'] . ' ' . $current['match_type'] . ' ' . $current['cert_data'];
+    }
+    unset($current);
+  }
+  else {
+    $currents = dns_get_record($record[0], $record_types[$record[1]]);
+    if ($record[1] == 'SRV') {
+      foreach ($currents as &$current) {
+        if ($current['target'] == '') {
+          $current['target'] = '.';
+          $current['port'] = '0';
+        }
+        $current['data'] = $current['target'] . ' ' . $current['port'];
+      }
+      unset($current);
+    }
+  }
+  
+  if ($record[1] == 'CNAME' && count($currents) == 0) {
+    // A and AAAA are also valid instead of CNAME
+    $a = dns_get_record($record[0], DNS_A);
+    $cname = dns_get_record($record[2], DNS_A);
+    if (count($a) > 0 && count($cname) > 0) {
+      if ($a[0]['ip'] == $cname[0]['ip']) {
+        $currents = array(array('host' => $record[0], 'class' => 'IN', 'type' => 'CNAME', 'target' => $record[2]));
+      
+        $aaaa = dns_get_record($record[0], DNS_AAAA);
+        $cname = dns_get_record($record[2], DNS_AAAA);
+        if (count($aaaa) == 0 || count($cname) == 0 || $aaaa[0]['ipv6'] != $cname[0]['ipv6']) {
+          $currents[0]['target'] = $aaaa[0]['ipv6'];
+        }
+      } else {
+        $currents = array(array('host' => $record[0], 'class' => 'IN', 'type' => 'CNAME', 'target' => $a[0]['ip']));
+      }
+    }
+  }
+  
+  foreach ($currents as $current) {
+    $current['type'] == strtoupper($current['type']);
+    if ($current['type'] != $record[1])
+    {
+      continue;
+    }
+    
+    elseif ($current['type'] == 'TXT' && strpos($record[0], '_dmarc.') === 0) {
+      $state = state_nomatch;
+      if (strpos($current[$data_field[$current['type']]], $record[3]) === 0)
+        $state = state_good . ' (' . current[$data_field[$current['type']]] . ')';
+    }
+    else if ($current['type'] == 'TXT' && strpos($current['txt'], 'v=spf1') === 0) {
+      $allowed = get_spf_allowed_hosts($record[0]);
+      $spf_ok = FALSE;
+      $spf_ok6 = FALSE;
+      foreach ($allowed as $net)
+      {
+        if (in_net($ip, $net))
+          $spf_ok = TRUE;
+        if (in_net($ip6, $net))
+          $spf_ok6 = TRUE;
+      }
+      if ($spf_ok && (empty($ip6) || $spf_ok6))
+        $state = state_good . ' (' . $current[$data_field[$current['type']]] . ')';
+    }
+    else if ($current['type'] != 'TXT' && isset($data_field[$current['type']]) && $state != state_good) {
+      $state = state_nomatch;
+      if ($current[$data_field[$current['type']]] == $record[2])
+        $state = state_good;
+    }
+  }
+  
+  if ($state == state_nomatch) {
+    $state = array();
+    foreach ($currents as $current) {
+      $state[] = $current[$data_field[$current['type']]];
+    }
+    $state = implode('<br />', $state);
+  }
+  
+  echo sprintf('<tr><td>%s</td><td>%s</td><td style="max-width: 300px; word-break: break-all">%s</td><td style="max-width: 150px; word-break: break-all">%s</td></tr>', $record[0], $record[1], $record[2], $state);
+}
+?>
+    </table>
+	</div>
+</div>
+<?php
+require_once("inc/footer.inc.php");
+} else {
+  header('Location: index.php');
+  exit();
+}
+?>