84 lines
4.9 KiB
HTML
84 lines
4.9 KiB
HTML
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<title>How to mark a mail domain as backup MX</title>
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// <a href="./index.html">Document Index</a></div><h1 id="how-to-mark-a-mail-domain-as-backup-mx">How to mark a mail domain as backup MX</h1>
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<div class="toc">
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<ul>
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<li><a href="#how-to-mark-a-mail-domain-as-backup-mx">How to mark a mail domain as backup MX</a><ul>
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<li><a href="#how-backup-mx-works-in-brief">How backup MX works in brief</a></li>
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<li><a href="#make-sure-you-have-correct-dns-records-for-the-mail-domain">Make sure you have correct DNS records for the mail domain</a></li>
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<li><a href="#mark-domain-as-backup-mx-with-iredadmin-pro">Mark domain as backup MX with iRedAdmin-Pro</a></li>
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<li><a href="#mark-domain-as-backup-mx-with-command-line-tools">Mark domain as backup MX with command line tools</a><ul>
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<li><a href="#for-sql-backends">For SQL backends</a></li>
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<li><a href="#for-ldap-backends">For LDAP backends</a></li>
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</ul>
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</li>
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<li><a href="#see-also">See also</a></li>
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</ul>
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</li>
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</ul>
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</div>
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<p>This tutorial describes how to mark a mail domain as a backup MX.</p>
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<h2 id="how-backup-mx-works-in-brief">How backup MX works in brief</h2>
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<p>When smtp service on primary MX server is down, emails will be delivered to
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backup MX server. When backup MX server detects smtp service on primary MX is
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back online, it will relay received emails to primary MX.</p>
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<h2 id="make-sure-you-have-correct-dns-records-for-the-mail-domain">Make sure you have correct DNS records for the mail domain</h2>
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<p>To let other mail servers know your server is the backup MX server of this
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mail domain, you must add your mail server info in its MX type DNS record.</p>
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<p>For example, main mail server of your mail domain <code>example.com</code> is
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<code>mx01.example.com</code>, to set your iRedMail server <code>mx02.example.com</code> as backup
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MX of <code>example.com</code>, you need to add <code>mx02.example.com</code> as your lower priority
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mail server in MX type DNS record.</p>
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<pre><code>example.com. 3600 IN MX 5 mx01.example.com
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example.com. 3600 IN MX 10 mx02.example.com
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</code></pre>
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<p>Server <code>mx01.example.com</code> has priority number <code>5</code>, and <code>mx02.example.com</code> has
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priority number <code>10</code>. For mail service, the lowest number has highest priority.
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so with above example, server <code>mx01.example.com</code> is the primary MX, and
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<code>mx02.example.com</code> is a backup MX.</p>
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<p>When mail service on <code>mx01.example.com</code> is down, other mail services will
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connect to <code>mx02.example.com</code>.</p>
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<h2 id="mark-domain-as-backup-mx-with-iredadmin-pro">Mark domain as backup MX with iRedAdmin-Pro</h2>
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<p>It's easy to manage domain profile With iRedAdmin-Pro, including backup MX setting.
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Go to domain profile page, click tab <code>Backup MX</code>:</p>
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<p><img alt="" src="./images/iredadmin/domain_profile_backupmx.png" width="1000px" /></p>
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<h2 id="mark-domain-as-backup-mx-with-command-line-tools">Mark domain as backup MX with command line tools</h2>
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<h3 id="for-sql-backends">For SQL backends</h3>
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<div class="admonition note">
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<p class="admonition-title">Primary server address</p>
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<p>It's recommended to set the IP address of primary MX as relay server to
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avoid mail loop.</p>
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</div>
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<p>SQL commands (we use MySQL for example):</p>
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<pre><code>USE vmail;
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UPDATE domain SET transport='relay:[45.56.127.226]:25',backupmx=1 WHERE domain='example.com';
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</code></pre>
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<p>In above example, we mark domain <code>example.com</code> as a backup MX, and use IP
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address <code>45.56.127.226</code> as primary MX server, you should replace it by the real
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IP address.</p>
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<h3 id="for-ldap-backends">For LDAP backends</h3>
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<p>In domain object, please add LDAP attribute/value pair like below:</p>
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<pre><code>domainBackupMX: yes
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mtaTransport: relay:[45.56.127.226]:25
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</code></pre>
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<h2 id="see-also">See also</h2>
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<ul>
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<li><a href="https://en.wikipedia.org/wiki/MX_record#The_backup_MX">Backup MX (wikipedia)</a></li>
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</ul><div class="footer">
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<p style="text-align: center; color: grey;">All documents are available in <a href="https://github.com/iredmail/docs/">GitHub repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. You can <a href="https://github.com/iredmail/docs/archive/master.zip">download the latest version</a> for offline reading. If you found something wrong, please do <a href="https://www.iredmail.org/contact.html">contact us</a> to fix it.</p>
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