ispmail-workaround-org/ispmail-bookworm/setting-dns-records/index.html
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</script> <ul class="top-level astro-3ii7xxms"> <li class="astro-3ii7xxms"> <details open class="astro-3ii7xxms"> <summary class="astro-3ii7xxms"> <span class="group-label astro-3ii7xxms"> <span class="large astro-3ii7xxms">ISPmail for Debian 13</span> </span> <svg aria-hidden="true" class="caret astro-3ii7xxms astro-c6vsoqas" width="16" height="16" viewBox="0 0 24 24" fill="currentColor" style="--sl-icon-size: 1.25rem;"><path d="m14.83 11.29-4.24-4.24a1 1 0 1 0-1.42 1.41L12.71 12l-3.54 3.54a1 1 0 0 0 0 1.41 1 1 0 0 0 .71.29 1 1 0 0 0 .71-.29l4.24-4.24a1.002 1.002 0 0 0 0-1.42Z"/></svg> </summary> <sl-sidebar-restore data-index="0"></sl-sidebar-restore> <ul class="astro-3ii7xxms"> <li class="astro-3ii7xxms"> <a href="/ispmail-trixie/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Start here</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/upgrading/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Upgrading from Debian Bookworm</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/install-debian/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Installing Debian</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/install-the-software-packages/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Install software packages</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/virtual-domains/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Virtual domains</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/database/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Database setup</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/overview/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Big picture</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/dns-records/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">DNS records</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/tls-certificate/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">TLS certificate</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/postfix/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Postfix</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/dovecot/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Dovecot</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/lmtp/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">LMTP</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/webmail/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Webmail using Roundcube</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/relaying/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Sending / Relaying</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/imap/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">IMAP</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/managing-users-aliases-and-domains/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Managing users, aliases and domains</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/catching-spam-with-rspamd/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Catching spam with rspamd</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/anti-spoofing-dkim-spf/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Prevent spoofing using DKIM and SPF</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/catch-all/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Catch-all addresses</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/quotas/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Quotas</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/going-live/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Going live</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-trixie/automated-installation/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Automated installation</span> </a> </li> </ul> </details> </li><li class="astro-3ii7xxms"> <details open class="astro-3ii7xxms"> <summary class="astro-3ii7xxms"> <span class="group-label astro-3ii7xxms"> <span class="large astro-3ii7xxms">ISPmail for Debian 12</span> </span> <svg aria-hidden="true" class="caret astro-3ii7xxms astro-c6vsoqas" width="16" height="16" viewBox="0 0 24 24" fill="currentColor" style="--sl-icon-size: 1.25rem;"><path d="m14.83 11.29-4.24-4.24a1 1 0 1 0-1.42 1.41L12.71 12l-3.54 3.54a1 1 0 0 0 0 1.41 1 1 0 0 0 .71.29 1 1 0 0 0 .71-.29l4.24-4.24a1.002 1.002 0 0 0 0-1.42Z"/></svg> </summary> <sl-sidebar-restore data-index="1"></sl-sidebar-restore> <ul class="astro-3ii7xxms"> <li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Start here</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/whats-new/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">What&#39;s new</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/migrating-from-a-bullseye-to-a-bookworm-server/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Migrating from your old (Bullseye) server</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/big-picture/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">The big picture</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/types-of-email-domains/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Types of email domains</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/install-debian-bookworm-on-your-server/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Installing Debian</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/install-the-software-packages/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Install software packages</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/creating-a-tls-encryption-key-and-certificate/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">TLS certificate</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/prepare-the-database/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Preparing the database</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/making-postfix-get-its-information-from-the-mariadb-database/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Let Postfix access MariaDB</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/catchall-aliases/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Catch-all aliases</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/setting-up-dovecot/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Setting up Dovecot</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/let-postfix-send-emails-to-dovecot/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Let Postfix send emails to Dovecot</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/quotas/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Quotas</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/testing-imap/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Testing IMAP</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/webmail-using-roundcube/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Webmail using Roundcube</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/testing-email-delivery/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Testing email delivery</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/relaying-outgoing-emails-through-postfix/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Relaying outgoing emails through Postfix</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/catching-spam-with-rspamd/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Catching spam with rspamd</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/setting-dns-records/" aria-current="page" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Setting DNS records</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/prevent-spoofing-using-dkim/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Prevent spoofing using DKIM</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/managing-users-aliases-and-domains/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Managing users, aliases and domains</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/monitoring-and-backup/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Monitoring and Backup</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/automatic-installation-with-ansible/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Automatic installation with Ansible</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/success-stories/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">Success stories</span> </a> </li><li class="astro-3ii7xxms"> <a href="/ispmail-bookworm/faq-frequently-asked-questions/" class="astro-3ii7xxms"> <span class="astro-3ii7xxms">FAQ (frequently asked questions)</span> </a> </li> </ul> </details> </li><li class="astro-3ii7xxms"> <details open class="astro-3ii7xxms"> <summary class="astro-3ii7xxms"> <span class="group-label astro-3ii7xxms"> <span class="large astro-3ii7xxms">Misc articles</span> </span> <svg aria-hidden="true" class="caret astro-3ii7xxms astro-c6vsoqas" width="16" height="16" viewBox="0 0 24 24" fill="currentColor" style="--sl-icon-size: 1.25rem;"><path d="m14.83 11.29-4.24-4.24a1 1 0 1 0-1.42 1.41L12.71 12l-3.54 3.54a1 1 0 0 0 0 1.41 1 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⚠️ This page is part of the ISPmail guide for Debian Bookworm. Please use the newer guide for <a href="/ispmail-trixie/" class="astro-kggsjsm4">Debian Trixie</a>.
</section> <div class="content-panel astro-7nkwcw3z"> <div class="sl-container astro-7nkwcw3z"> <h1 id="_top" class="astro-j6tvhyss">Setting DNS records</h1> </div> </div> <div class="content-panel astro-7nkwcw3z"> <div class="sl-container astro-7nkwcw3z"> <div class="sl-markdown-content"> <div class="sl-heading-wrapper level-h2"><h2 id="mx-entries">MX entries</h2><a class="sl-anchor-link" href="#mx-entries"><span aria-hidden="true" class="sl-anchor-icon"><svg width="16" height="16" viewBox="0 0 24 24"><path fill="currentcolor" d="m12.11 15.39-3.88 3.88a2.52 2.52 0 0 1-3.5 0 2.47 2.47 0 0 1 0-3.5l3.88-3.88a1 1 0 0 0-1.42-1.42l-3.88 3.89a4.48 4.48 0 0 0 6.33 6.33l3.89-3.88a1 1 0 1 0-1.42-1.42Zm8.58-12.08a4.49 4.49 0 0 0-6.33 0l-3.89 3.88a1 1 0 0 0 1.42 1.42l3.88-3.88a2.52 2.52 0 0 1 3.5 0 2.47 2.47 0 0 1 0 3.5l-3.88 3.88a1 1 0 1 0 1.42 1.42l3.88-3.89a4.49 4.49 0 0 0 0-6.33ZM8.83 15.17a1 1 0 0 0 1.1.22 1 1 0 0 0 .32-.22l4.92-4.92a1 1 0 0 0-1.42-1.42l-4.92 4.92a1 1 0 0 0 0 1.42Z"></path></svg></span><span class="sr-only" data-pagefind-ignore>Section titled “MX entries”</span></a></div>
<p>So now you have your working mail server. But how do other mail servers get to know you? The answer lies in the most important service on the internet: <a href="http://en.wikipedia.org/wiki/Domain_Name_System">DNS</a> the Domain Name System. Assume that a mail server somewhere on the other end of the internet wants to send an email to <code dir="auto">john@example.org</code>. The server must find out the name (and IP address) of the mail server responsible for the example.org domain. This is how that works:</p>
<p><img src="/_astro/setting-dns-records-mx-big-picture.y_PGYrNz_Z1iCyv.webp" alt="Big picture of how MX records work" loading="lazy" decoding="async" width="513" height="372"></p>
<p>The remote server queries its DNS server for the MX (Mail eXchanger) record of the “example.org” domain. (If no MX record was found it tries again and asks for A (address) records. Thats a fallback solution.) Lets run a query for a real domain to get an idea. Lets ask which servers receive email for …@gmail.com.</p>
<div class="expressive-code"><link rel="stylesheet" href="/_astro/ec.v4551.css"><script type="module" src="/_astro/ec.0vx5m.js"></script><figure class="frame not-content"><figcaption class="header"></figcaption><pre data-language="plaintext"><code><div class="ec-line"><div class="code"><span style="--0:#d6deeb;--1:#403f53">$> host -t MX gmail.com</span></div></div><div class="ec-line"><div class="code"><span style="--0:#d6deeb;--1:#403f53">gmail.com mail is handled by 10 alt1.gmail-smtp-in.l.google.com.</span></div></div><div class="ec-line"><div class="code"><span style="--0:#d6deeb;--1:#403f53">gmail.com mail is handled by 20 alt2.gmail-smtp-in.l.google.com.</span></div></div><div class="ec-line"><div class="code"><span style="--0:#d6deeb;--1:#403f53">gmail.com mail is handled by 30 alt3.gmail-smtp-in.l.google.com.</span></div></div><div class="ec-line"><div class="code"><span style="--0:#d6deeb;--1:#403f53">gmail.com mail is handled by 40 alt4.gmail-smtp-in.l.google.com.</span></div></div><div class="ec-line"><div class="code"><span style="--0:#d6deeb;--1:#403f53">gmail.com mail is handled by 5 gmail-smtp-in.l.google.com.</span></div></div></code></pre><div class="copy"><div aria-live="polite"></div><button title="Copy to clipboard" data-copied="Copied!" data-code="$> host -t MX gmail.comgmail.com mail is handled by 10 alt1.gmail-smtp-in.l.google.com.gmail.com mail is handled by 20 alt2.gmail-smtp-in.l.google.com.gmail.com mail is handled by 30 alt3.gmail-smtp-in.l.google.com.gmail.com mail is handled by 40 alt4.gmail-smtp-in.l.google.com.gmail.com mail is handled by 5 gmail-smtp-in.l.google.com."><div></div></button></div></figure></div>
<p>So as a result we get 5 different MX records. Each of them consists of a numeric priority and the host name of the mail server. A mail server would pick the entry with the highest priority (=the lowest number) and establish an SMTP connection to that host. In this example that would be the priority 5 server gmail-smtp-in.l.google.com. If that server could not be reached then the next best server with priority 10 would be used and so on. So all you have to do in your own DNS zone is add an MX entry pointing to your mail server. If you want to run a backup mail server (which is outside of the scope of this tutorial) then you can add a second entry with a an equal or lower priority.</p>
<p>A mistake some people make is using an IP address in MX records. That is not allowed. An MX record always points to a host name. You will have to add an A record for your MX record to point to the actual IP address of your mail server.</p>
<aside aria-label="For fun and science" class="starlight-aside starlight-aside--tip"> <p class="starlight-aside__title" aria-hidden="true"> <svg aria-hidden="true" class="starlight-aside__icon astro-c6vsoqas" width="16" height="16" viewBox="0 0 24 24" fill="currentColor" style="--sl-icon-size: 1em;"><path fill-rule="evenodd" d="M1.44 8.855v-.001l3.527-3.516c.34-.344.802-.541 1.285-.548h6.649l.947-.947c3.07-3.07 6.207-3.072 7.62-2.868a1.821 1.821 0 0 1 1.557 1.557c.204 1.413.203 4.55-2.868 7.62l-.946.946v6.649a1.845 1.845 0 0 1-.549 1.286l-3.516 3.528a1.844 1.844 0 0 1-3.11-.944l-.858-4.275-4.52-4.52-2.31-.463-1.964-.394A1.847 1.847 0 0 1 .98 10.693a1.843 1.843 0 0 1 .46-1.838Zm5.379 2.017-3.873-.776L6.32 6.733h4.638l-4.14 4.14Zm8.403-5.655c2.459-2.46 4.856-2.463 5.89-2.33.134 1.035.13 3.432-2.329 5.891l-6.71 6.71-3.561-3.56 6.71-6.711Zm-1.318 15.837-.776-3.873 4.14-4.14v4.639l-3.364 3.374Z" clip-rule="evenodd"/><path d="M9.318 18.345a.972.972 0 0 0-1.86-.561c-.482 1.435-1.687 2.204-2.934 2.619a8.22 8.22 0 0 1-1.23.302c.062-.365.157-.79.303-1.229.415-1.247 1.184-2.452 2.62-2.935a.971.971 0 1 0-.62-1.842c-.12.04-.236.084-.35.13-2.02.828-3.012 2.588-3.493 4.033a10.383 10.383 0 0 0-.51 2.845l-.001.016v.063c0 .536.434.972.97.972H2.24a7.21 7.21 0 0 0 .878-.065c.527-.063 1.248-.19 2.02-.447 1.445-.48 3.205-1.472 4.033-3.494a5.828 5.828 0 0 0 .147-.407Z"/></svg>For fun and science </p> <div class="starlight-aside__content"><p>In the above example it is very unlikely that a mail server will ever have to use the server with priority 40. Adventurous system administrators can add such a low-priority entry and see who connects to it. An interesting observation is that spammers often try these servers first hoping that it is just for backup purposes and less restrictive or lazily configured than the main server. If you see someone connecting to the lowest-priority address first without having tried a higher-priority mail server then you can be pretty certain that its not a friend whos knocking at your door.</p></div> </aside>
<div class="sl-heading-wrapper level-h2"><h2 id="fallback-to-a-entries">Fallback to A entries</h2><a class="sl-anchor-link" href="#fallback-to-a-entries"><span aria-hidden="true" class="sl-anchor-icon"><svg width="16" height="16" viewBox="0 0 24 24"><path fill="currentcolor" d="m12.11 15.39-3.88 3.88a2.52 2.52 0 0 1-3.5 0 2.47 2.47 0 0 1 0-3.5l3.88-3.88a1 1 0 0 0-1.42-1.42l-3.88 3.89a4.48 4.48 0 0 0 6.33 6.33l3.89-3.88a1 1 0 1 0-1.42-1.42Zm8.58-12.08a4.49 4.49 0 0 0-6.33 0l-3.89 3.88a1 1 0 0 0 1.42 1.42l3.88-3.88a2.52 2.52 0 0 1 3.5 0 2.47 2.47 0 0 1 0 3.5l-3.88 3.88a1 1 0 1 0 1.42 1.42l3.88-3.89a4.49 4.49 0 0 0 0-6.33ZM8.83 15.17a1 1 0 0 0 1.1.22 1 1 0 0 0 .32-.22l4.92-4.92a1 1 0 0 0-1.42-1.42l-4.92 4.92a1 1 0 0 0 0 1.42Z"></path></svg></span><span class="sr-only" data-pagefind-ignore>Section titled “Fallback to A entries”</span></a></div>
<p>It is advised to explicitly name mail servers for your domain in the MX records. If you cant do that for whatever reason then the remote mail server will just do an A record lookup for the IP address and then send email there. If you just run one server for both the web service and the email service then you can do that. But if the web server for your domain is located at another IP address than your mail server then this wont work.</p>
<div class="sl-heading-wrapper level-h2"><h2 id="reverse-dns">Reverse DNS</h2><a class="sl-anchor-link" href="#reverse-dns"><span aria-hidden="true" class="sl-anchor-icon"><svg width="16" height="16" viewBox="0 0 24 24"><path fill="currentcolor" d="m12.11 15.39-3.88 3.88a2.52 2.52 0 0 1-3.5 0 2.47 2.47 0 0 1 0-3.5l3.88-3.88a1 1 0 0 0-1.42-1.42l-3.88 3.89a4.48 4.48 0 0 0 6.33 6.33l3.89-3.88a1 1 0 1 0-1.42-1.42Zm8.58-12.08a4.49 4.49 0 0 0-6.33 0l-3.89 3.88a1 1 0 0 0 1.42 1.42l3.88-3.88a2.52 2.52 0 0 1 3.5 0 2.47 2.47 0 0 1 0 3.5l-3.88 3.88a1 1 0 1 0 1.42 1.42l3.88-3.89a4.49 4.49 0 0 0 0-6.33ZM8.83 15.17a1 1 0 0 0 1.1.22 1 1 0 0 0 .32-.22l4.92-4.92a1 1 0 0 0-1.42-1.42l-4.92 4.92a1 1 0 0 0 0 1.42Z"></path></svg></span><span class="sr-only" data-pagefind-ignore>Section titled “Reverse DNS”</span></a></div>
<p>Many mail servers check that your forward (name to IP) and reverse (IP to name) lead to the same results. This is how it should look:</p>
<p>example.org —(MX)> mx.example.org<br>
mx.example.org —(A)> 1.2.3.4<br>
1.2.3.4 —(PTR)> mx.example.org</p>
<p>(1.2.3.4 in a PTR record is actually 4.3.2.1.in-addr.arpa.)</p>
<div class="sl-heading-wrapper level-h2"><h2 id="ipv6">IPv6</h2><a class="sl-anchor-link" href="#ipv6"><span aria-hidden="true" class="sl-anchor-icon"><svg width="16" height="16" viewBox="0 0 24 24"><path fill="currentcolor" d="m12.11 15.39-3.88 3.88a2.52 2.52 0 0 1-3.5 0 2.47 2.47 0 0 1 0-3.5l3.88-3.88a1 1 0 0 0-1.42-1.42l-3.88 3.89a4.48 4.48 0 0 0 6.33 6.33l3.89-3.88a1 1 0 1 0-1.42-1.42Zm8.58-12.08a4.49 4.49 0 0 0-6.33 0l-3.89 3.88a1 1 0 0 0 1.42 1.42l3.88-3.88a2.52 2.52 0 0 1 3.5 0 2.47 2.47 0 0 1 0 3.5l-3.88 3.88a1 1 0 1 0 1.42 1.42l3.88-3.89a4.49 4.49 0 0 0 0-6.33ZM8.83 15.17a1 1 0 0 0 1.1.22 1 1 0 0 0 .32-.22l4.92-4.92a1 1 0 0 0-1.42-1.42l-4.92 4.92a1 1 0 0 0 0 1.42Z"></path></svg></span><span class="sr-only" data-pagefind-ignore>Section titled “IPv6”</span></a></div>
<p>Fortunately many ISPs finally start to offer IPv6 in their networks. So if you rent a virtual server from a provider then check if you also got an IPv6 address assigned. In that case you also need to have proper DNS records for that as well. Like:</p>
<p>example.org —(MX)> mx.example.org<br>
mx.example.org —(AAAA)> fdeb:37d7:ef39:e063::1<br>
fdeb:37d7:ef39:e063 —(PTR)> mx.example.org</p>
<p>Chances are that you havent dealt with IPv6 yet. Give it a try. IP addresses may look different at first but you will never again have to deal with odd subnet sizes or NAT. Thank me later. 🙂</p> </div> <footer> <footer class="sl-flex astro-3yyafb3n"> <div class="meta sl-flex astro-3yyafb3n"> <p>Last updated: <time datetime="2023-10-04T00:00:00.000Z">Oct 4, 2023</time></p> </div> <div class="pagination-links print:hidden astro-u2l5gyhi" dir="ltr"> <a href="/ispmail-bookworm/catching-spam-with-rspamd/" rel="prev" class="astro-u2l5gyhi"> <svg aria-hidden="true" class="astro-u2l5gyhi astro-c6vsoqas" width="16" height="16" viewBox="0 0 24 24" fill="currentColor" style="--sl-icon-size: 1.5rem;"><path d="M17 11H9.41l3.3-3.29a1.004 1.004 0 1 0-1.42-1.42l-5 5a1 1 0 0 0-.21.33 1 1 0 0 0 0 .76 1 1 0 0 0 .21.33l5 5a1.002 1.002 0 0 0 1.639-.325 1 1 0 0 0-.219-1.095L9.41 13H17a1 1 0 0 0 0-2Z"/></svg> <span class="astro-u2l5gyhi"> Previous <br class="astro-u2l5gyhi"> <span class="link-title astro-u2l5gyhi">Catching spam with rspamd</span> </span> </a> <a href="/ispmail-bookworm/prevent-spoofing-using-dkim/" rel="next" class="astro-u2l5gyhi"> <svg aria-hidden="true" class="astro-u2l5gyhi astro-c6vsoqas" width="16" height="16" viewBox="0 0 24 24" fill="currentColor" style="--sl-icon-size: 1.5rem;"><path d="M17.92 11.62a1.001 1.001 0 0 0-.21-.33l-5-5a1.003 1.003 0 1 0-1.42 1.42l3.3 3.29H7a1 1 0 0 0 0 2h7.59l-3.3 3.29a1.002 1.002 0 0 0 .325 1.639 1 1 0 0 0 1.095-.219l5-5a1 1 0 0 0 .21-.33 1 1 0 0 0 0-.76Z"/></svg> <span class="astro-u2l5gyhi"> Next <br class="astro-u2l5gyhi"> <span class="link-title astro-u2l5gyhi">Prevent spoofing using DKIM</span> </span> </a> </div> </footer> <script defer src="https://comentario.workaround.org/comentario.js"></script>
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