github-com-docker-mailserver/docker-mailserver
1
0
Fork 0
mirror of https://github.com/docker-mailserver/docker-mailserver.git synced 2024-01-19 02:48:50 +00:00
Code Issues Projects Releases Wiki Activity
docker-mailserver/v10.0/config/best-practices/spf/index.html
github-actions[bot] 5a0b5e3c5c deploy: a0f4a37512
2021-06-01 11:09:18 +00:00

1423 lines
39 KiB
HTML
Raw Blame History

<!doctype html>
<html lang="en" class="no-js">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="A fullstack but simple mail server (SMTP, IMAP, LDAP, Antispam, Antivirus, etc.) using Docker.">
<meta name="author" content="docker-mailserver (Github Organization)">
<link rel="canonical" href="https://docker-mailserver.github.io/docker-mailserver/edge/config/best-practices/spf/">
<link rel="icon" href="../../../assets/logo/favicon-32x32.png">
<meta name="generator" content="mkdocs-1.1.2, mkdocs-material-7.1.6">
<title>Best Practices | SPF - Docker Mailserver</title>
<link rel="stylesheet" href="../../../assets/stylesheets/main.875de78c.min.css">
<link rel="stylesheet" href="../../../assets/stylesheets/palette.f1a3b89f.min.css">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,400,400i,700%7CRoboto+Mono&display=fallback">
<style>:root{--md-text-font-family:"Roboto";--md-code-font-family:"Roboto Mono"}</style>
<link rel="stylesheet" href="../../../assets/css/customizations.css">
</head>
<body dir="ltr" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo">
<script>function __prefix(e){return new URL("../../..",location).pathname+"."+e}function __get(e,t=localStorage){return JSON.parse(t.getItem(__prefix(e)))}</script>
<script>var palette=__get("__palette");if(null!==palette&&"object"==typeof palette.color)for(var key in palette.color)document.body.setAttribute("data-md-color-"+key,palette.color[key])</script>
<input class="md-toggle" data-md-toggle="drawer" type="checkbox" id="__drawer" autocomplete="off">
<input class="md-toggle" data-md-toggle="search" type="checkbox" id="__search" autocomplete="off">
<label class="md-overlay" for="__drawer"></label>
<div data-md-component="skip">
<a href="#add-a-spf-record" class="md-skip">
Skip to content
</a>
</div>
<div data-md-component="announce">
</div>
<header class="md-header" data-md-component="header">
<nav class="md-header__inner md-grid" aria-label="Header">
<a href="../../.." title="Docker Mailserver" class="md-header__button md-logo" aria-label="Docker Mailserver" data-md-component="logo">
<img src="../../../assets/logo/dmo-logo-white.min.svg" alt="logo">
</a>
<label class="md-header__button md-icon" for="__drawer">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M3 6h18v2H3V6m0 5h18v2H3v-2m0 5h18v2H3v-2z"/></svg>
</label>
<div class="md-header__title" data-md-component="header-title">
<div class="md-header__ellipsis">
<div class="md-header__topic">
<span class="md-ellipsis">
Docker Mailserver
</span>
</div>
<div class="md-header__topic" data-md-component="header-topic">
<span class="md-ellipsis">
Best Practices | SPF
</span>
</div>
</div>
</div>
<form class="md-header__option" data-md-component="palette">
<input class="md-option" data-md-color-media="(prefers-color-scheme: light)" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo" type="radio" name="__palette" id="__palette_1">
<label class="md-header__button md-icon" title="Switch to dark mode" for="__palette_2" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="m17.75 4.09-2.53 1.94.91 3.06-2.63-1.81-2.63 1.81.91-3.06-2.53-1.94L12.44 4l1.06-3 1.06 3 3.19.09m3.5 6.91-1.64 1.25.59 1.98-1.7-1.17-1.7 1.17.59-1.98L15.75 11l2.06-.05L18.5 9l.69 1.95 2.06.05m-2.28 4.95c.83-.08 1.72 1.1 1.19 1.85-.32.45-.66.87-1.08 1.27C15.17 23 8.84 23 4.94 19.07c-3.91-3.9-3.91-10.24 0-14.14.4-.4.82-.76 1.27-1.08.75-.53 1.93.36 1.85 1.19-.27 2.86.69 5.83 2.89 8.02a9.96 9.96 0 0 0 8.02 2.89m-1.64 2.02a12.08 12.08 0 0 1-7.8-3.47c-2.17-2.19-3.33-5-3.49-7.82-2.81 3.14-2.7 7.96.31 10.98 3.02 3.01 7.84 3.12 10.98.31z"/></svg>
</label>
<input class="md-option" data-md-color-media="(prefers-color-scheme: dark)" data-md-color-scheme="slate" data-md-color-primary="indigo" data-md-color-accent="blue" type="radio" name="__palette" id="__palette_2">
<label class="md-header__button md-icon" title="Switch to light mode" for="__palette_1" hidden>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M12 7a5 5 0 0 1 5 5 5 5 0 0 1-5 5 5 5 0 0 1-5-5 5 5 0 0 1 5-5m0 2a3 3 0 0 0-3 3 3 3 0 0 0 3 3 3 3 0 0 0 3-3 3 3 0 0 0-3-3m0-7 2.39 3.42C13.65 5.15 12.84 5 12 5c-.84 0-1.65.15-2.39.42L12 2M3.34 7l4.16-.35A7.2 7.2 0 0 0 5.94 8.5c-.44.74-.69 1.5-.83 2.29L3.34 7m.02 10 1.76-3.77a7.131 7.131 0 0 0 2.38 4.14L3.36 17M20.65 7l-1.77 3.79a7.023 7.023 0 0 0-2.38-4.15l4.15.36m-.01 10-4.14.36c.59-.51 1.12-1.14 1.54-1.86.42-.73.69-1.5.83-2.29L20.64 17M12 22l-2.41-3.44c.74.27 1.55.44 2.41.44.82 0 1.63-.17 2.37-.44L12 22z"/></svg>
</label>
</form>
<label class="md-header__button md-icon" for="__search">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.516 6.516 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5z"/></svg>
</label>
<div class="md-search" data-md-component="search" role="dialog">
<label class="md-search__overlay" for="__search"></label>
<div class="md-search__inner" role="search">
<form class="md-search__form" name="search">
<input type="text" class="md-search__input" name="query" aria-label="Search" placeholder="Search" autocapitalize="off" autocorrect="off" autocomplete="off" spellcheck="false" data-md-component="search-query" data-md-state="active" required>
<label class="md-search__icon md-icon" for="__search">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M9.5 3A6.5 6.5 0 0 1 16 9.5c0 1.61-.59 3.09-1.56 4.23l.27.27h.79l5 5-1.5 1.5-5-5v-.79l-.27-.27A6.516 6.516 0 0 1 9.5 16 6.5 6.5 0 0 1 3 9.5 6.5 6.5 0 0 1 9.5 3m0 2C7 5 5 7 5 9.5S7 14 9.5 14 14 12 14 9.5 12 5 9.5 5z"/></svg>
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11h12z"/></svg>
</label>
<button type="reset" class="md-search__icon md-icon" aria-label="Clear" tabindex="-1">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M19 6.41 17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12 19 6.41z"/></svg>
</button>
</form>
<div class="md-search__output">
<div class="md-search__scrollwrap" data-md-scrollfix>
<div class="md-search-result" data-md-component="search-result">
<div class="md-search-result__meta">
Initializing search
</div>
<ol class="md-search-result__list"></ol>
</div>
</div>
</div>
</div>
</div>
<div class="md-header__source">
<a href="https://github.com/docker-mailserver/docker-mailserver/" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 496 512"><path d="M165.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6zm-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3zm44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9zM244.8 8C106.1 8 0 113.3 0 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C428.2 457.8 496 362.9 496 252 496 113.3 383.5 8 244.8 8zM97.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1zm-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7zm32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1zm-11.4-14.7c-1.6 1-1.6 3.6 0 5.9 1.6 2.3 4.3 3.3 5.6 2.3 1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2z"/></svg>
</div>
<div class="md-source__repository">
docker-mailserver
</div>
</a>
</div>
</nav>
</header>
<div class="md-container" data-md-component="container">
<nav class="md-tabs" aria-label="Tabs" data-md-component="tabs">
<div class="md-tabs__inner md-grid">
<ul class="md-tabs__list">
<li class="md-tabs__item">
<a href="../../.." class="md-tabs__link">
Home
</a>
</li>
<li class="md-tabs__item">
<a href="../../../introduction/" class="md-tabs__link">
Introduction
</a>
</li>
<li class="md-tabs__item">
<a href="../../setup.sh/" class="md-tabs__link md-tabs__link--active">
Configuration
</a>
</li>
<li class="md-tabs__item">
<a href="../../../examples/tutorials/basic-installation/" class="md-tabs__link">
Examples
</a>
</li>
<li class="md-tabs__item">
<a href="../../../faq/" class="md-tabs__link">
FAQ
</a>
</li>
<li class="md-tabs__item">
<a href="../../../contributing/issues-and-pull-requests/" class="md-tabs__link">
Contributing
</a>
</li>
<li class="md-tabs__item">
<a href="https://hub.docker.com/repository/docker/mailserver/docker-mailserver" class="md-tabs__link">
DockerHub
</a>
</li>
<li class="md-tabs__item">
<a href="https://github.com/orgs/docker-mailserver/packages/container/package/docker-mailserver" class="md-tabs__link">
GHCR
</a>
</li>
</ul>
</div>
</nav>
<main class="md-main" data-md-component="main">
<div class="md-main__inner md-grid">
<div class="md-sidebar md-sidebar--primary" data-md-component="sidebar" data-md-type="navigation" >
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--primary md-nav--lifted" aria-label="Navigation" data-md-level="0">
<label class="md-nav__title" for="__drawer">
<a href="../../.." title="Docker Mailserver" class="md-nav__button md-logo" aria-label="Docker Mailserver" data-md-component="logo">
<img src="../../../assets/logo/dmo-logo-white.min.svg" alt="logo">
</a>
Docker Mailserver
</label>
<div class="md-nav__source">
<a href="https://github.com/docker-mailserver/docker-mailserver/" title="Go to repository" class="md-source" data-md-component="source">
<div class="md-source__icon md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 496 512"><path d="M165.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6zm-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3zm44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9zM244.8 8C106.1 8 0 113.3 0 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C428.2 457.8 496 362.9 496 252 496 113.3 383.5 8 244.8 8zM97.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1zm-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7zm32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1zm-11.4-14.7c-1.6 1-1.6 3.6 0 5.9 1.6 2.3 4.3 3.3 5.6 2.3 1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2z"/></svg>
</div>
<div class="md-source__repository">
docker-mailserver
</div>
</a>
</div>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../.." class="md-nav__link">
Home
</a>
</li>
<li class="md-nav__item">
<a href="../../../introduction/" class="md-nav__link">
Introduction
</a>
</li>
<li class="md-nav__item md-nav__item--active md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3" type="checkbox" id="__nav_3" checked>
<label class="md-nav__link" for="__nav_3">
Configuration
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Configuration" data-md-level="1">
<label class="md-nav__title" for="__nav_3">
<span class="md-nav__icon md-icon"></span>
Configuration
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../setup.sh/" class="md-nav__link">
Your Best Friend setup.sh
</a>
</li>
<li class="md-nav__item">
<a href="../../environment/" class="md-nav__link">
Environment Variables
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_3" data-md-state="indeterminate" type="checkbox" id="__nav_3_3" checked>
<label class="md-nav__link" for="__nav_3_3">
User Management
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="User Management" data-md-level="2">
<label class="md-nav__title" for="__nav_3_3">
<span class="md-nav__icon md-icon"></span>
User Management
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../user-management/accounts/" class="md-nav__link">
Accounts
</a>
</li>
<li class="md-nav__item">
<a href="../../user-management/aliases/" class="md-nav__link">
Aliases
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--active md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_4" type="checkbox" id="__nav_3_4" checked>
<label class="md-nav__link" for="__nav_3_4">
Best Practices
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Best Practices" data-md-level="2">
<label class="md-nav__title" for="__nav_3_4">
<span class="md-nav__icon md-icon"></span>
Best Practices
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../dkim/" class="md-nav__link">
DKIM
</a>
</li>
<li class="md-nav__item">
<a href="../dmarc/" class="md-nav__link">
DMARC
</a>
</li>
<li class="md-nav__item md-nav__item--active">
<input class="md-nav__toggle md-toggle" data-md-toggle="toc" type="checkbox" id="__toc">
<label class="md-nav__link md-nav__link--active" for="__toc">
SPF
<span class="md-nav__icon md-icon"></span>
</label>
<a href="./" class="md-nav__link md-nav__link--active">
SPF
</a>
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#add-a-spf-record" class="md-nav__link">
Add a SPF Record
</a>
</li>
<li class="md-nav__item">
<a href="#backup-mx-secondary-mx" class="md-nav__link">
Backup MX, Secondary MX
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../autodiscover/" class="md-nav__link">
Auto-discovery
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_5" data-md-state="indeterminate" type="checkbox" id="__nav_3_5" checked>
<label class="md-nav__link" for="__nav_3_5">
Security
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Security" data-md-level="2">
<label class="md-nav__title" for="__nav_3_5">
<span class="md-nav__icon md-icon"></span>
Security
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../security/understanding-the-ports/" class="md-nav__link">
Understanding the Ports
</a>
</li>
<li class="md-nav__item">
<a href="../../security/ssl/" class="md-nav__link">
SSL/TLS
</a>
</li>
<li class="md-nav__item">
<a href="../../security/fail2ban/" class="md-nav__link">
Fail2Ban
</a>
</li>
<li class="md-nav__item">
<a href="../../security/mail_crypt/" class="md-nav__link">
Mail Encryption
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_6" data-md-state="indeterminate" type="checkbox" id="__nav_3_6" checked>
<label class="md-nav__link" for="__nav_3_6">
Troubleshooting
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Troubleshooting" data-md-level="2">
<label class="md-nav__title" for="__nav_3_6">
<span class="md-nav__icon md-icon"></span>
Troubleshooting
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../troubleshooting/debugging/" class="md-nav__link">
Debugging
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../pop3/" class="md-nav__link">
Mail Delivery with POP3
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_8" data-md-state="indeterminate" type="checkbox" id="__nav_3_8" checked>
<label class="md-nav__link" for="__nav_3_8">
Advanced Configuration
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Advanced Configuration" data-md-level="2">
<label class="md-nav__title" for="__nav_3_8">
<span class="md-nav__icon md-icon"></span>
Advanced Configuration
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../advanced/optional-config/" class="md-nav__link">
Optional Configuration
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_8_2" data-md-state="indeterminate" type="checkbox" id="__nav_3_8_2" checked>
<label class="md-nav__link" for="__nav_3_8_2">
Maintenance
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Maintenance" data-md-level="3">
<label class="md-nav__title" for="__nav_3_8_2">
<span class="md-nav__icon md-icon"></span>
Maintenance
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../advanced/maintenance/update-and-cleanup/" class="md-nav__link">
Update and Cleanup
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_8_3" data-md-state="indeterminate" type="checkbox" id="__nav_3_8_3" checked>
<label class="md-nav__link" for="__nav_3_8_3">
Override the Default Configs
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Override the Default Configs" data-md-level="3">
<label class="md-nav__title" for="__nav_3_8_3">
<span class="md-nav__icon md-icon"></span>
Override the Default Configs
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../advanced/override-defaults/dovecot/" class="md-nav__link">
Dovecot
</a>
</li>
<li class="md-nav__item">
<a href="../../advanced/override-defaults/postfix/" class="md-nav__link">
Postfix
</a>
</li>
<li class="md-nav__item">
<a href="../../advanced/override-defaults/user-patches/" class="md-nav__link">
Modifications via Script
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../advanced/auth-ldap/" class="md-nav__link">
LDAP Authentication
</a>
</li>
<li class="md-nav__item">
<a href="../../advanced/mail-sieve/" class="md-nav__link">
Email Filtering with Sieve
</a>
</li>
<li class="md-nav__item">
<a href="../../advanced/mail-fetchmail/" class="md-nav__link">
Email Gathering with Fetchmail
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_3_8_7" data-md-state="indeterminate" type="checkbox" id="__nav_3_8_7" checked>
<label class="md-nav__link" for="__nav_3_8_7">
Email Forwarding
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Email Forwarding" data-md-level="3">
<label class="md-nav__title" for="__nav_3_8_7">
<span class="md-nav__icon md-icon"></span>
Email Forwarding
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../advanced/mail-forwarding/relay-hosts/" class="md-nav__link">
Relay Hosts
</a>
</li>
<li class="md-nav__item">
<a href="../../advanced/mail-forwarding/aws-ses/" class="md-nav__link">
AWS SES
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../advanced/full-text-search/" class="md-nav__link">
Full-Text Search
</a>
</li>
<li class="md-nav__item">
<a href="../../advanced/kubernetes/" class="md-nav__link">
Kubernetes
</a>
</li>
<li class="md-nav__item">
<a href="../../advanced/ipv6/" class="md-nav__link">
IPv6
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_4" data-md-state="indeterminate" type="checkbox" id="__nav_4" checked>
<label class="md-nav__link" for="__nav_4">
Examples
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Examples" data-md-level="1">
<label class="md-nav__title" for="__nav_4">
<span class="md-nav__icon md-icon"></span>
Examples
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_4_1" data-md-state="indeterminate" type="checkbox" id="__nav_4_1" checked>
<label class="md-nav__link" for="__nav_4_1">
Tutorials
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Tutorials" data-md-level="2">
<label class="md-nav__title" for="__nav_4_1">
<span class="md-nav__icon md-icon"></span>
Tutorials
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../../examples/tutorials/basic-installation/" class="md-nav__link">
Basic Installation
</a>
</li>
<li class="md-nav__item">
<a href="../../../examples/tutorials/mailserver-behind-proxy/" class="md-nav__link">
Mailserver behind Proxy
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_4_2" data-md-state="indeterminate" type="checkbox" id="__nav_4_2" checked>
<label class="md-nav__link" for="__nav_4_2">
Use Cases
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Use Cases" data-md-level="2">
<label class="md-nav__title" for="__nav_4_2">
<span class="md-nav__icon md-icon"></span>
Use Cases
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../../examples/uses-cases/forward-only-mailserver-with-ldap-authentication/" class="md-nav__link">
Forward-Only Mailserver with LDAP
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../../faq/" class="md-nav__link">
FAQ
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle" data-md-toggle="__nav_6" data-md-state="indeterminate" type="checkbox" id="__nav_6" checked>
<label class="md-nav__link" for="__nav_6">
Contributing
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" aria-label="Contributing" data-md-level="1">
<label class="md-nav__title" for="__nav_6">
<span class="md-nav__icon md-icon"></span>
Contributing
</label>
<ul class="md-nav__list" data-md-scrollfix>
<li class="md-nav__item">
<a href="../../../contributing/issues-and-pull-requests/" class="md-nav__link">
Issues and Pull Requests
</a>
</li>
<li class="md-nav__item">
<a href="../../../contributing/coding-style/" class="md-nav__link">
Coding Style
</a>
</li>
<li class="md-nav__item">
<a href="../../../contributing/tests/" class="md-nav__link">
Tests
</a>
</li>
<li class="md-nav__item">
<a href="../../../contributing/documentation/" class="md-nav__link">
Documentation
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="https://hub.docker.com/repository/docker/mailserver/docker-mailserver" class="md-nav__link">
DockerHub
</a>
</li>
<li class="md-nav__item">
<a href="https://github.com/orgs/docker-mailserver/packages/container/package/docker-mailserver" class="md-nav__link">
GHCR
</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-sidebar md-sidebar--secondary" data-md-component="sidebar" data-md-type="toc" hidden>
<div class="md-sidebar__scrollwrap">
<div class="md-sidebar__inner">
<nav class="md-nav md-nav--secondary" aria-label="Table of contents">
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
Table of contents
</label>
<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#add-a-spf-record" class="md-nav__link">
Add a SPF Record
</a>
</li>
<li class="md-nav__item">
<a href="#backup-mx-secondary-mx" class="md-nav__link">
Backup MX, Secondary MX
</a>
</li>
</ul>
</nav>
</div>
</div>
</div>
<div class="md-content" data-md-component="content">
<article class="md-content__inner md-typeset">
<a href="https://github.com/docker-mailserver/docker-mailserver/edit/master/docs/content/config/best-practices/spf.md" title="Edit this page" class="md-content__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20.71 7.04c.39-.39.39-1.04 0-1.41l-2.34-2.34c-.37-.39-1.02-.39-1.41 0l-1.84 1.83 3.75 3.75M3 17.25V21h3.75L17.81 9.93l-3.75-3.75L3 17.25z"/></svg>
</a>
<h1>SPF</h1>
<p>From <a href="https://en.wikipedia.org/wiki/Sender_Policy_Framework">Wikipedia</a>:</p>
<div class="admonition quote">
<p class="admonition-title">Quote</p>
<p>Sender Policy Framework (SPF) is a simple email-validation system designed to detect email spoofing by providing a mechanism to allow receiving mail exchangers to check that incoming mail from a domain comes from a host authorized by that domain's administrators. The list of authorized sending hosts for a domain is published in the Domain Name System (DNS) records for that domain in the form of a specially formatted TXT record. Email spam and phishing often use forged "from" addresses, so publishing and checking SPF records can be considered anti-spam techniques.</p>
</div>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>For a more technical review: <a href="https://github.com/internetstandards/toolbox-wiki/blob/master/SPF-how-to.md">https://github.com/internetstandards/toolbox-wiki/blob/master/SPF-how-to.md</a></p>
</div>
<h2 id="add-a-spf-record"><a class="toclink" href="#add-a-spf-record">Add a SPF Record</a></h2>
<p>To add a SPF record in your DNS, insert the following line in your DNS zone:</p>
<div class="highlight"><pre><span></span><code>; MX record must be declared for SPF to work
domain.com. IN MX 1 mail.domain.com.
; SPF record
domain.com. IN TXT &quot;v=spf1 mx ~all&quot;
</code></pre></div>
<p>This enables the <em>Softfail</em> mode for SPF. You could first add this SPF record with a very low TTL.<br />
<em>SoftFail</em> is a good setting for getting started and testing, as it lets all email through, with spams tagged as such in the mailbox.</p>
<p>After verification, you <em>might</em> want to change your SPF record to <code>v=spf1 mx -all</code> so as to enforce the <em>HardFail</em> policy. See <a href="http://www.open-spf.org/SPF_Record_Syntax">http://www.open-spf.org/SPF_Record_Syntax</a> for more details about SPF policies.</p>
<p>In any case, increment the SPF record's TTL to its final value.</p>
<h2 id="backup-mx-secondary-mx"><a class="toclink" href="#backup-mx-secondary-mx">Backup MX, Secondary MX</a></h2>
<p>For whitelisting a IP Address from the SPF test, you can create a config file (see <a href="https://www.linuxcertif.com/man/5/policyd-spf.conf"><code>policyd-spf.conf</code></a>) and mount that file into <code>/etc/postfix-policyd-spf-python/policyd-spf.conf</code>.</p>
<p><strong>Example:</strong></p>
<p>Create and edit a <code>policyd-spf.conf</code> file here <code>/&lt;your docker-mailserver dir&gt;/config/postfix-policyd-spf.conf</code>:</p>
<div class="highlight"><pre><span></span><code><span class="na">debugLevel</span> <span class="o">=</span> <span class="s">1</span>
<span class="c1">#0(only errors)-4(complete data received)</span>
<span class="na">skip_addresses</span> <span class="o">=</span> <span class="s">127.0.0.0/8,::ffff:127.0.0.0/104,::1</span>
<span class="c1"># Preferably use IP-Addresses for whitelist lookups:</span>
<span class="na">Whitelist</span> <span class="o">=</span> <span class="s">192.168.0.0/31,192.168.1.0/30</span>
<span class="c1"># Domain_Whitelist = mx1.mybackupmx.com,mx2.mybackupmx.com</span>
</code></pre></div>
<p>Then add this line to <code>docker-compose.yml</code>:</p>
<div class="highlight"><pre><span></span><code><span class="nt">volumes</span><span class="p">:</span>
<span class="p p-Indicator">-</span> <span class="l l-Scalar l-Scalar-Plain">./config/postfix-policyd-spf.conf:/etc/postfix-policyd-spf-python/policyd-spf.conf</span>
</code></pre></div>
</article>
</div>
</div>
<a href="#" class="md-top md-icon" title="Back to top" data-md-component="top" data-md-state="hidden">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M13 20h-2V8l-5.5 5.5-1.42-1.42L12 4.16l7.92 7.92-1.42 1.42L13 8v12z"/></svg>
</a>
</main>
<footer class="md-footer">
<nav class="md-footer__inner md-grid" aria-label="Footer">
<a href="../dmarc/" class="md-footer__link md-footer__link--prev" rel="prev">
<div class="md-footer__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 11v2H8l5.5 5.5-1.42 1.42L4.16 12l7.92-7.92L13.5 5.5 8 11h12z"/></svg>
</div>
<div class="md-footer__title">
<div class="md-ellipsis">
<span class="md-footer__direction">
Previous
</span>
DMARC
</div>
</div>
</a>
<a href="../autodiscover/" class="md-footer__link md-footer__link--next" rel="next">
<div class="md-footer__title">
<div class="md-ellipsis">
<span class="md-footer__direction">
Next
</span>
Auto-discovery
</div>
</div>
<div class="md-footer__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M4 11v2h12l-5.5 5.5 1.42 1.42L19.84 12l-7.92-7.92L10.5 5.5 16 11H4z"/></svg>
</div>
</a>
</nav>
<div class="md-footer-meta md-typeset">
<div class="md-footer-meta__inner md-grid">
<div class="md-footer-copyright">
<div class="md-footer-copyright__highlight">
<p>&copy <a href="https://github.com/docker-mailserver"><em>Docker Mailserver Organization</em></a><br/><span>This project is licensed under the MIT license.</span></p>
</div>
Made with
<a href="https://squidfunk.github.io/mkdocs-material/" target="_blank" rel="noopener">
Material for MkDocs
</a>
</div>
</div>
</div>
</footer>
</div>
<div class="md-dialog" data-md-component="dialog">
<div class="md-dialog__inner md-typeset"></div>
</div>
<script id="__config" type="application/json">{"base": "../../..", "features": ["navigation.tabs", "navigation.top", "navigation.expand", "navigation.instant"], "translations": {"clipboard.copy": "Copy to clipboard", "clipboard.copied": "Copied to clipboard", "search.config.lang": "en", "search.config.pipeline": "trimmer, stopWordFilter", "search.config.separator": "[\\s\\-]+", "search.placeholder": "Search", "search.result.placeholder": "Type to start searching", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.term.missing": "Missing"}, "search": "../../../assets/javascripts/workers/search.d351de03.min.js", "version": {"provider": "mike"}}</script>
<script src="../../../assets/javascripts/bundle.34eae1b6.min.js"></script>
</body>
</html>
Reference in a new issue View git blame Copy permalink