docker-mailserver/v13.1/config/debugging/index.html

2268 lines
57 KiB
HTML
Raw Normal View 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/latest/config/debugging/">
<link rel="prev" href="../security/rspamd/">
<link rel="next" href="../pop3/">
<link rel="icon" href="../../assets/logo/favicon-32x32.png">
<meta name="generator" content="mkdocs-1.5.2, mkdocs-material-9.2.8">
<title>Debugging - Docker Mailserver</title>
<link rel="stylesheet" href="../../assets/stylesheets/main.046329b4.min.css">
<link rel="stylesheet" href="../../assets/stylesheets/palette.85d0ee34.min.css">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,300i,400,400i,700,700i%7CRoboto+Mono:400,400i,700,700i&display=fallback">
<style>:root{--md-text-font:"Roboto";--md-code-font:"Roboto Mono"}</style>
<link rel="stylesheet" href="../../assets/css/customizations.css">
<script>__md_scope=new URL("../..",location),__md_hash=e=>[...e].reduce((e,_)=>(e<<5)-e+_.charCodeAt(0),0),__md_get=(e,_=localStorage,t=__md_scope)=>JSON.parse(_.getItem(t.pathname+"."+e)),__md_set=(e,_,t=localStorage,a=__md_scope)=>{try{t.setItem(a.pathname+"."+e,JSON.stringify(_))}catch(e){}}</script>
</head>
<body dir="ltr" data-md-color-scheme="default" data-md-color-primary="indigo" data-md-color-accent="indigo">
<script>var palette=__md_get("__palette");if(palette&&"object"==typeof palette.color)for(var key of Object.keys(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="#preliminary-checks" class="md-skip">
Skip to content
</a>
</div>
<div data-md-component="announce">
</div>
<div data-md-color-scheme="default" data-md-component="outdated" hidden>
</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">
Debugging
</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" aria-label="Switch to dark mode" 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" aria-label="Switch to light mode" 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" 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>
<nav class="md-search__options" aria-label="Search">
<button type="reset" class="md-search__icon md-icon" title="Clear" 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>
</nav>
</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" role="presentation"></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"><!--! Font Awesome Free 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2023 Fonticons, Inc.--><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-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="../../usage/" class="md-tabs__link">
Usage
</a>
</li>
<li class="md-tabs__item md-tabs__item--active">
<a href="../environment/" class="md-tabs__link">
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/general/" class="md-tabs__link">
Contributing
</a>
</li>
<li class="md-tabs__item">
<a href="https://hub.docker.com/r/mailserver/docker-mailserver/" class="md-tabs__link">
DockerHub
</a>
</li>
<li class="md-tabs__item">
<a href="https://github.com/docker-mailserver/docker-mailserver/pkgs/container/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"><!--! Font Awesome Free 6.4.2 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2023 Fonticons, Inc.--><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">
<span class="md-ellipsis">
Home
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../introduction/" class="md-nav__link">
<span class="md-ellipsis">
Introduction
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../usage/" class="md-nav__link">
<span class="md-ellipsis">
Usage
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--active md-nav__item--nested">
<input class="md-nav__toggle md-toggle " type="checkbox" id="__nav_4" checked>
<label class="md-nav__link" for="__nav_4" id="__nav_4_label" tabindex="0">
<span class="md-ellipsis">
Configuration
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_4_label" aria-expanded="true">
<label class="md-nav__title" for="__nav_4">
<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="../environment/" class="md-nav__link">
<span class="md-ellipsis">
Environment Variables
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../user-management/" class="md-nav__link">
<span class="md-ellipsis">
User Management
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_4_3" >
<label class="md-nav__link" for="__nav_4_3" id="__nav_4_3_label" tabindex="0">
<span class="md-ellipsis">
Best Practices
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_4_3_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_3">
<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="../best-practices/dkim_dmarc_spf/" class="md-nav__link">
<span class="md-ellipsis">
DKIM, DMARC & SPF
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../best-practices/autodiscover/" class="md-nav__link">
<span class="md-ellipsis">
Auto-discovery
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_4_4" >
<label class="md-nav__link" for="__nav_4_4" id="__nav_4_4_label" tabindex="0">
<span class="md-ellipsis">
Security
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_4_4_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_4">
<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">
<span class="md-ellipsis">
Understanding the Ports
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../security/ssl/" class="md-nav__link">
<span class="md-ellipsis">
SSL/TLS
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../security/fail2ban/" class="md-nav__link">
<span class="md-ellipsis">
Fail2Ban
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../security/mail_crypt/" class="md-nav__link">
<span class="md-ellipsis">
Mail Encryption
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../security/rspamd/" class="md-nav__link">
<span class="md-ellipsis">
Rspamd
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--active">
<input class="md-nav__toggle md-toggle" type="checkbox" id="__toc">
<label class="md-nav__link md-nav__link--active" for="__toc">
<span class="md-ellipsis">
Debugging
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<a href="./" class="md-nav__link md-nav__link--active">
<span class="md-ellipsis">
Debugging
</span>
</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="#preliminary-checks" class="md-nav__link">
Preliminary Checks
</a>
<nav class="md-nav" aria-label="Preliminary Checks">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#mail-sent-from-dms-does-not-arrive-at-destination" class="md-nav__link">
Mail sent from DMS does not arrive at destination
</a>
</li>
<li class="md-nav__item">
<a href="#mail-sent-to-dms-does-not-get-delivered-to-user" class="md-nav__link">
Mail sent to DMS does not get delivered to user
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="#steps-for-debugging-dms" class="md-nav__link">
Steps for Debugging DMS
</a>
<nav class="md-nav" aria-label="Steps for Debugging DMS">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#debug-a-running-container" class="md-nav__link">
Debug a running container
</a>
<nav class="md-nav" aria-label="Debug a running container">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#general" class="md-nav__link">
General
</a>
</li>
<li class="md-nav__item">
<a href="#logs" class="md-nav__link">
Logs
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="#compatibility" class="md-nav__link">
Compatibility
</a>
<nav class="md-nav" aria-label="Compatibility">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#network" class="md-nav__link">
Network
</a>
</li>
<li class="md-nav__item">
<a href="#system" class="md-nav__link">
System
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../pop3/" class="md-nav__link">
<span class="md-ellipsis">
Mail Delivery with POP3
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../setup.sh/" class="md-nav__link">
<span class="md-ellipsis">
About setup.sh
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_4_8" >
<label class="md-nav__link" for="__nav_4_8" id="__nav_4_8_label" tabindex="0">
<span class="md-ellipsis">
Advanced Configuration
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_4_8_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_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">
<span class="md-ellipsis">
Optional Configuration
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_4_8_2" >
<label class="md-nav__link" for="__nav_4_8_2" id="__nav_4_8_2_label" tabindex="0">
<span class="md-ellipsis">
Maintenance
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="3" aria-labelledby="__nav_4_8_2_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_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">
<span class="md-ellipsis">
Update and Cleanup
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_4_8_3" >
<label class="md-nav__link" for="__nav_4_8_3" id="__nav_4_8_3_label" tabindex="0">
<span class="md-ellipsis">
Override the Default Configs
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="3" aria-labelledby="__nav_4_8_3_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_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">
<span class="md-ellipsis">
Dovecot
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/override-defaults/postfix/" class="md-nav__link">
<span class="md-ellipsis">
Postfix
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/override-defaults/user-patches/" class="md-nav__link">
<span class="md-ellipsis">
Modifications via Script
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../advanced/auth-ldap/" class="md-nav__link">
<span class="md-ellipsis">
LDAP Authentication
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/mail-sieve/" class="md-nav__link">
<span class="md-ellipsis">
Email Filtering with Sieve
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/mail-fetchmail/" class="md-nav__link">
<span class="md-ellipsis">
Email Gathering with Fetchmail
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/mail-getmail/" class="md-nav__link">
<span class="md-ellipsis">
Email Gathering with Getmail
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_4_8_8" >
<label class="md-nav__link" for="__nav_4_8_8" id="__nav_4_8_8_label" tabindex="0">
<span class="md-ellipsis">
Email Forwarding
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="3" aria-labelledby="__nav_4_8_8_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_4_8_8">
<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">
<span class="md-ellipsis">
Relay Hosts
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/mail-forwarding/aws-ses/" class="md-nav__link">
<span class="md-ellipsis">
AWS SES
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../advanced/full-text-search/" class="md-nav__link">
<span class="md-ellipsis">
Full-Text Search
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/kubernetes/" class="md-nav__link">
<span class="md-ellipsis">
Kubernetes
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/ipv6/" class="md-nav__link">
<span class="md-ellipsis">
IPv6
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/podman/" class="md-nav__link">
<span class="md-ellipsis">
Podman
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../advanced/dovecot-master-accounts/" class="md-nav__link">
<span class="md-ellipsis">
Dovecot Master Accounts
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_5" >
<label class="md-nav__link" for="__nav_5" id="__nav_5_label" tabindex="0">
<span class="md-ellipsis">
Examples
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_5_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_5">
<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 md-toggle--indeterminate" type="checkbox" id="__nav_5_1" >
<label class="md-nav__link" for="__nav_5_1" id="__nav_5_1_label" tabindex="0">
<span class="md-ellipsis">
Tutorials
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_5_1_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_5_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">
<span class="md-ellipsis">
Basic Installation
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../examples/tutorials/mailserver-behind-proxy/" class="md-nav__link">
<span class="md-ellipsis">
Mailserver behind Proxy
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../examples/tutorials/crowdsec/" class="md-nav__link">
<span class="md-ellipsis">
Crowdsec
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../examples/tutorials/docker-build/" class="md-nav__link">
<span class="md-ellipsis">
Building your own Docker image
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../examples/tutorials/blog-posts/" class="md-nav__link">
<span class="md-ellipsis">
Blog Posts
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_5_2" >
<label class="md-nav__link" for="__nav_5_2" id="__nav_5_2_label" tabindex="0">
<span class="md-ellipsis">
Use Cases
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="2" aria-labelledby="__nav_5_2_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_5_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/use-cases/forward-only-mailserver-with-ldap-authentication/" class="md-nav__link">
<span class="md-ellipsis">
Forward-Only Mail-Server with LDAP
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../examples/use-cases/imap-folders/" class="md-nav__link">
<span class="md-ellipsis">
Customize IMAP Folders
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../examples/use-cases/ios-mail-push-support/" class="md-nav__link">
<span class="md-ellipsis">
iOS Mail Push Support
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../examples/use-cases/auth-lua/" class="md-nav__link">
<span class="md-ellipsis">
Lua Authentication
</span>
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="../../faq/" class="md-nav__link">
<span class="md-ellipsis">
FAQ
</span>
</a>
</li>
<li class="md-nav__item md-nav__item--nested">
<input class="md-nav__toggle md-toggle md-toggle--indeterminate" type="checkbox" id="__nav_7" >
<label class="md-nav__link" for="__nav_7" id="__nav_7_label" tabindex="0">
<span class="md-ellipsis">
Contributing
</span>
<span class="md-nav__icon md-icon"></span>
</label>
<nav class="md-nav" data-md-level="1" aria-labelledby="__nav_7_label" aria-expanded="false">
<label class="md-nav__title" for="__nav_7">
<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/general/" class="md-nav__link">
<span class="md-ellipsis">
General Information
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../contributing/tests/" class="md-nav__link">
<span class="md-ellipsis">
Tests
</span>
</a>
</li>
<li class="md-nav__item">
<a href="../../contributing/issues-and-pull-requests/" class="md-nav__link">
<span class="md-ellipsis">
Issues and Pull Requests
</span>
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="https://hub.docker.com/r/mailserver/docker-mailserver/" class="md-nav__link">
<span class="md-ellipsis">
DockerHub
</span>
</a>
</li>
<li class="md-nav__item">
<a href="https://github.com/docker-mailserver/docker-mailserver/pkgs/container/docker-mailserver" class="md-nav__link">
<span class="md-ellipsis">
GHCR
</span>
</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="#preliminary-checks" class="md-nav__link">
Preliminary Checks
</a>
<nav class="md-nav" aria-label="Preliminary Checks">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#mail-sent-from-dms-does-not-arrive-at-destination" class="md-nav__link">
Mail sent from DMS does not arrive at destination
</a>
</li>
<li class="md-nav__item">
<a href="#mail-sent-to-dms-does-not-get-delivered-to-user" class="md-nav__link">
Mail sent to DMS does not get delivered to user
</a>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="#steps-for-debugging-dms" class="md-nav__link">
Steps for Debugging DMS
</a>
<nav class="md-nav" aria-label="Steps for Debugging DMS">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#debug-a-running-container" class="md-nav__link">
Debug a running container
</a>
<nav class="md-nav" aria-label="Debug a running container">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#general" class="md-nav__link">
General
</a>
</li>
<li class="md-nav__item">
<a href="#logs" class="md-nav__link">
Logs
</a>
</li>
</ul>
</nav>
</li>
</ul>
</nav>
</li>
<li class="md-nav__item">
<a href="#compatibility" class="md-nav__link">
Compatibility
</a>
<nav class="md-nav" aria-label="Compatibility">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#network" class="md-nav__link">
Network
</a>
</li>
<li class="md-nav__item">
<a href="#system" class="md-nav__link">
System
</a>
</li>
</ul>
</nav>
</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/debugging.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="M10 20H6V4h7v5h5v3.1l2-2V8l-6-6H6c-1.1 0-2 .9-2 2v16c0 1.1.9 2 2 2h4v-2m10.2-7c.1 0 .3.1.4.2l1.3 1.3c.2.2.2.6 0 .8l-1 1-2.1-2.1 1-1c.1-.1.2-.2.4-.2m0 3.9L14.1 23H12v-2.1l6.1-6.1 2.1 2.1Z"/></svg>
</a>
<a href="https://github.com/docker-mailserver/docker-mailserver/raw/master/docs/content/config/debugging.md" title="View source of this page" class="md-content__button md-icon">
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M17 18c.56 0 1 .44 1 1s-.44 1-1 1-1-.44-1-1 .44-1 1-1m0-3c-2.73 0-5.06 1.66-6 4 .94 2.34 3.27 4 6 4s5.06-1.66 6-4c-.94-2.34-3.27-4-6-4m0 6.5a2.5 2.5 0 0 1-2.5-2.5 2.5 2.5 0 0 1 2.5-2.5 2.5 2.5 0 0 1 2.5 2.5 2.5 2.5 0 0 1-2.5 2.5M9.27 20H6V4h7v5h5v4.07c.7.08 1.36.25 2 .49V8l-6-6H6a2 2 0 0 0-2 2v16a2 2 0 0 0 2 2h4.5a8.15 8.15 0 0 1-1.23-2Z"/></svg>
</a>
<h1>Debugging</h1>
<p>This page contains valuable information when it comes to resolving issues you encounter.</p>
<div class="admonition info">
<p class="admonition-title">Contributions Welcome!</p>
<p>Please consider contributing solutions to the <a href="../../faq/">FAQ</a> <img alt="❤" class="twemoji" src="https://cdn.jsdelivr.net/gh/jdecked/twemoji@14.1.2/assets/svg/2764.svg" title=":heart:" /></p>
</div>
<h2 id="preliminary-checks"><a class="toclink" href="#preliminary-checks">Preliminary Checks</a></h2>
<ul>
<li>Check that all published DMS ports are actually open and not blocked by your ISP / hosting provider.</li>
<li>SSL errors are likely the result of a wrong setup on the user side and not caused by DMS itself.</li>
<li>Ensure that you have correctly started DMS. Many problems related to configuration are due to this.</li>
</ul>
<div class="admonition danger">
<p class="admonition-title">Correctly starting DMS</p>
<p>Use the <a href="https://docs.docker.com/compose/reference/up/"><code>--force-recreate</code></a> option to avoid configuration mishaps: <code>docker compose up --force-recreate</code></p>
<p>Alternatively, always use <code>docker compose down</code> to stop DMS. <strong>Do not</strong> rely on <code>CTRL + C</code>, <code>docker compose stop</code>, or <code>docker compose restart</code>.</p>
<hr />
<p>DMS setup scripts are run when a container starts, but may fail to work properly if you do the following:</p>
<ul>
<li>Stopping a container with commands like: <code>docker stop</code> or <code>docker compose up</code> stopped via <code>CTRL + C</code> instead of <code>docker compose down</code>.</li>
<li>Restarting a container.</li>
</ul>
<p>Volumes persist data across container instances, however the same container instance will keep internal changes not stored in a volume until the container is removed.</p>
<p>Due to this, DMS setup scripts may modify configuration it has already modified in the past.</p>
<ul>
<li>This is brittle as some changes are naive by assuming they are applied to the original configs from the image.</li>
<li>Volumes in <code>compose.yaml</code> are expected to persist any important data. Thus it should be safe to throwaway the container created each time, avoiding this config problem.</li>
</ul>
</div>
<h3 id="mail-sent-from-dms-does-not-arrive-at-destination"><a class="toclink" href="#mail-sent-from-dms-does-not-arrive-at-destination">Mail sent from DMS does not arrive at destination</a></h3>
<p>Some service providers block outbound traffic on port 25. Common hosting providers known to have this issue:</p>
<ul>
<li><a href="https://docs.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity">Azure</a></li>
<li><a href="https://aws.amazon.com/premiumsupport/knowledge-center/ec2-port-25-throttle/">AWS EC2</a></li>
<li><a href="https://www.vultr.com/docs/what-ports-are-blocked/">Vultr</a></li>
</ul>
<p>These links may advise how the provider can unblock the port through additional services offered, or via a support ticket request.</p>
<h3 id="mail-sent-to-dms-does-not-get-delivered-to-user"><a class="toclink" href="#mail-sent-to-dms-does-not-get-delivered-to-user">Mail sent to DMS does not get delivered to user</a></h3>
<p>Common logs related to this are:</p>
<ul>
<li><code>warning: do not list domain domain.fr in BOTH mydestination and virtual_mailbox_domains</code></li>
<li><code>Recipient address rejected: User unknown in local recipient table</code></li>
</ul>
<p>If your logs look like this, you likely have <a href="https://github.com/docker-mailserver/docker-mailserver/issues/3679#issuecomment-1837609043">assigned the same FQDN to the DMS <code>hostname</code> and your mail accounts</a> which is not supported by default. You can either adjust your DMS <code>hostname</code> or follow <a href="../../faq/#can-i-use-a-nakedbare-domain-ie-no-hostname">this FAQ advice</a></p>
<p>It is also possible that <a href="https://github.com/docker-mailserver/docker-mailserver/issues/3679#issuecomment-1848083358">DMS services are temporarily unavailable</a> when configuration changes are detected, producing the 2nd error. Certificate updates may be a less obvious trigger.</p>
<h2 id="steps-for-debugging-dms"><a class="toclink" href="#steps-for-debugging-dms">Steps for Debugging DMS</a></h2>
<ol>
<li><strong>Increase log verbosity</strong>: Very helpful for troubleshooting problems during container startup. Set the environment variable <a href="../environment/#log_level"><code>LOG_LEVEL</code></a> to <code>debug</code> or <code>trace</code>.</li>
<li><strong>Use error logs as a search query</strong>: Try <a href="https://github.com/docker-mailserver/docker-mailserver/issues">finding an <em>existing issue</em></a> or <em>search engine result</em> from any errors in your container log output. Often you'll find answers or more insights. If you still need to open an issue, sharing links from your search may help us assist you. The mail server log can be acquired by running <code>docker log &lt;CONTAINER NAME&gt;</code> (<em>or <code>docker logs -f &lt;CONTAINER NAME&gt;</code> if you want to follow the log</em>).</li>
<li><strong>Inspect the logs of the service that is failing</strong>: We provide a dedicated paragraph on this topic <a href="#logs">further down below</a>.</li>
<li><strong>Understand the basics of mail servers</strong>: Especially for beginners, make sure you read our <a href="../../introduction/">Introduction</a> and <a href="../../usage/">Usage</a> articles.</li>
<li><strong>Search the whole FAQ</strong>: Our <a href="../../faq/">FAQ</a> contains answers for common problems. Make sure you go through the list.</li>
<li><strong>Reduce the scope</strong>: Ensure that you can run a basic setup of DMS first. Then incrementally restore parts of your original configuration until the problem is reproduced again. If you're new to DMS, it is common to find the cause is misunderstanding how to configure a minimal setup.</li>
</ol>
<h3 id="debug-a-running-container"><a class="toclink" href="#debug-a-running-container">Debug a running container</a></h3>
<h4 id="general"><a class="toclink" href="#general">General</a></h4>
<p>To get a shell inside the container run: <code>docker exec -it &lt;CONTAINER NAME&gt; bash</code>. To install additional software, run:</p>
<ol>
<li><code>apt-get update</code> to update repository metadata.</li>
<li><code>apt-get install &lt;PACKAGE&gt;</code> to install a package, e.g., <code>apt-get install neovim</code> if you want to use NeoVim instead of <code>nano</code> (which is shipped by default).</li>
</ol>
<h4 id="logs"><a class="toclink" href="#logs">Logs</a></h4>
<p>If you need more flexibility than what the <code>docker logs</code> command offers, then the most useful locations to get relevant DMS logs within the container are:</p>
<ul>
<li><code>/var/log/mail/&lt;SERVICE&gt;.log</code></li>
<li><code>/var/log/supervisor/&lt;SERVICE&gt;.log</code></li>
</ul>
<p>You may use <code>nano</code> (a text editor) to edit files, while <code>less</code> (a file viewer) and <code>tail</code>/<code>cat</code> are useful tools to inspect the contents of logs.</p>
<h2 id="compatibility"><a class="toclink" href="#compatibility">Compatibility</a></h2>
<p>It's possible that the issue you're experiencing is due to a compatibility conflict.</p>
<p>This could be from outdated software, or running a system that isn't able to provide you newer software and kernels. You may want to verify if you can reproduce the issue on a system that is not affected by these concerns.</p>
<h3 id="network"><a class="toclink" href="#network">Network</a></h3>
<ul>
<li>Misconfigured network connections can cause the client IP address to be proxied through a docker network gateway IP, or a <a href="https://github.com/orgs/docker-mailserver/discussions/3273#discussioncomment-5654603">service that acts on behalf of connecting clients for logins</a> where the connections client IP appears to be only from that service (eg: Container IP) instead. This can relay the wrong information to other services (eg: monitoring like Fail2Ban, SPF verification) causing unexpected failures.</li>
<li><strong><code>userland-proxy</code>:</strong> Prior to Docker <code>v23</code>, <a href="https://github.com/moby/moby/issues/44721">changing the <code>userland-proxy</code> setting did not reliably remove NAT rules</a>.</li>
<li><strong>UFW / firewalld:</strong> Some users expect only their firewall frontend to manage the firewall rules, but these will be bypassed when Docker publishes a container port (<em>as there is no integration between the two</em>).</li>
<li><strong><code>iptables</code> / <code>nftables</code>:</strong><ul>
<li>Docker <a href="https://github.com/moby/moby/issues/26824">only manages the NAT rules via <code>iptables</code></a>, relying on compatibility shims for supporting the successor <code>nftables</code>. Internally DMS expects <code>nftables</code> support on the host kernel for services like Fail2Ban to function correctly.</li>
<li><a href="https://unix.stackexchange.com/questions/596493/can-nftables-and-iptables-ip6tables-rules-be-applied-at-the-same-time-if-so-wh/596497#596497">Kernels older than 5.2 may affect management of NAT rules via <code>nftables</code></a>. Other software outside of DMS may also manipulate these rules, such as firewall frontends.</li>
</ul>
</li>
<li><strong>IPv6:</strong><ul>
<li>Requires <a href="../advanced/ipv6/">additional configuration</a> to prevent or properly support IPv6 connections (eg: Preserving the Client IP).</li>
<li>Support in 2023 is still considered experimental. You are advised to use at least Docker Engine <code>v23</code> (2023Q1).</li>
<li>Various networking bug fixes have been addressed since the initial IPv6 support arrived in Docker Engine <code>v20.10.0</code> (2020Q4).</li>
</ul>
</li>
</ul>
<h3 id="system"><a class="toclink" href="#system">System</a></h3>
<ul>
<li><strong>macOS:</strong> DMS has limited support for macOS. Often an issue encountered is due to permissions related to the <code>volumes</code> config in <code>compose.yaml</code>. You may have luck <a href="https://github.com/docker-mailserver/docker-mailserver/issues/3648#issuecomment-1822774080">trying <code>gRPC FUSE</code></a> as the file sharing implementation; <a href="https://www.docker.com/blog/speed-boost-achievement-unlocked-on-docker-desktop-4-6-for-mac/"><code>VirtioFS</code> is the successor</a> but presently appears incompatible with DMS.</li>
<li><strong>Kernel:</strong> Some systems provide <a href="https://github.com/docker-mailserver/docker-mailserver/pull/2662#issuecomment-1168435970">kernels with modifications (<em>replacing defaults and backporting patches</em>)</a> to support running legacy software or kernels, complicating compatibility. This can be commonly experienced with products like NAS.</li>
<li><strong>CGroups v2:</strong> Hosts running older kernels (prior to 5.2) and systemd (prior to v244) are not likely to leverage cgroup v2, or have not defaulted to the cgroup v2 <code>unified</code> hierarchy. Not meeting this baseline may influence the behaviour of your DMS container, even with the latest Docker Engine installed.</li>
<li><strong>Container runtime:</strong> Docker and Podman for example have subtle differences. DMS docs are primarily focused on Docker, but we try to document known issues where relevant.</li>
<li><strong>Rootless containers:</strong> Introduces additional differences in behaviour or requirements:<ul>
<li>cgroup v2 is required for supporting rootless containers.</li>
<li>Differences such as for container networking which may further affect support for IPv6 and preserving the client IP (Remote address). Example with Docker rootless are <a href="https://github.com/moby/moby/issues/45742">binding a port to a specific interface</a> and the choice of <a href="../security/fail2ban/#running-inside-a-rootless-container">port forwarding driver</a>.</li>
</ul>
</li>
</ul>
</article>
</div>
</div>
<button type="button" class="md-top md-icon" data-md-component="top" 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>
Back to top
</button>
</main>
<footer class="md-footer">
<div class="md-footer-meta md-typeset">
<div class="md-footer-meta__inner md-grid">
<div class="md-copyright">
<div class="md-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", "content.action.edit", "content.action.view", "content.code.annotate"], "search": "../../assets/javascripts/workers/search.dfff1995.min.js", "translations": {"clipboard.copied": "Copied to clipboard", "clipboard.copy": "Copy to clipboard", "search.result.more.one": "1 more on this page", "search.result.more.other": "# more on this page", "search.result.none": "No matching documents", "search.result.one": "1 matching document", "search.result.other": "# matching documents", "search.result.placeholder": "Type to start searching", "search.result.term.missing": "Missing", "select.version": "Select version"}, "version": {"provider": "mike"}}</script>
<script src="../../assets/javascripts/bundle.dff1b7c8.min.js"></script>
</body>
</html>