Mirrors
/
synapse-old
mirror of https://github.com/matrix-org/synapse.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
synapse-old/v1.45.0/MSC1711_certificates_FAQ.html

531 lines
38 KiB
HTML
Raw Normal View History

deploy: b1c1a34f4680f89e5de506444155081c380dae97
2021-10-19 03:57:29 -06:00
<!DOCTYPE HTML>
<html lang="en" class="sidebar-visible no-js light">
<head>
<!-- Book generated using mdBook -->
<meta charset="UTF-8">
<title>Upgrading from pre-Synapse 1.0 - Synapse</title>
<!-- Custom HTML head -->
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
<meta name="description" content="">
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="theme-color" content="#ffffff" />
<link rel="icon" href="favicon.svg">
<link rel="shortcut icon" href="favicon.png">
<link rel="stylesheet" href="css/variables.css">
<link rel="stylesheet" href="css/general.css">
<link rel="stylesheet" href="css/chrome.css">
<link rel="stylesheet" href="css/print.css" media="print">
<!-- Fonts -->
<link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
<link rel="stylesheet" href="fonts/fonts.css">
<!-- Highlight.js Stylesheets -->
<link rel="stylesheet" href="highlight.css">
<link rel="stylesheet" href="tomorrow-night.css">
<link rel="stylesheet" href="ayu-highlight.css">
<!-- Custom theme stylesheets -->
<link rel="stylesheet" href="docs/website_files/table-of-contents.css">
<link rel="stylesheet" href="docs/website_files/remove-nav-buttons.css">
<link rel="stylesheet" href="docs/website_files/indent-section-headers.css">
</head>
<body>
<!-- Provide site root to javascript -->
<script type="text/javascript">
var path_to_root = "";
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light";
</script>
<!-- Work around some values being stored in localStorage wrapped in quotes -->
<script type="text/javascript">
try {
var theme = localStorage.getItem('mdbook-theme');
var sidebar = localStorage.getItem('mdbook-sidebar');
if (theme.startsWith('"') && theme.endsWith('"')) {
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
}
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
}
} catch (e) { }
</script>
<!-- Set the theme before any content is loaded, prevents flash -->
<script type="text/javascript">
var theme;
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
if (theme === null || theme === undefined) { theme = default_theme; }
var html = document.querySelector('html');
html.classList.remove('no-js')
html.classList.remove('light')
html.classList.add(theme);
html.classList.add('js');
</script>
<!-- Hide / unhide sidebar before it is displayed -->
<script type="text/javascript">
var html = document.querySelector('html');
var sidebar = 'hidden';
if (document.body.clientWidth >= 1080) {
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
sidebar = sidebar || 'visible';
}
html.classList.remove('sidebar-visible');
html.classList.add("sidebar-" + sidebar);
</script>
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
<div class="sidebar-scrollbox">
<ol class="chapter"><li class="chapter-item expanded affix "><li class="part-title">Introduction</li><li class="chapter-item expanded "><a href="welcome_and_overview.html">Welcome and Overview</a></li><li class="chapter-item expanded affix "><li class="part-title">Setup</li><li class="chapter-item expanded "><a href="setup/installation.html">Installation</a></li><li class="chapter-item expanded "><a href="postgres.html">Using Postgres</a></li><li class="chapter-item expanded "><a href="reverse_proxy.html">Configuring a Reverse Proxy</a></li><li class="chapter-item expanded "><a href="setup/forward_proxy.html">Configuring a Forward/Outbound Proxy</a></li><li class="chapter-item expanded "><a href="turn-howto.html">Configuring a Turn Server</a></li><li class="chapter-item expanded "><a href="delegate.html">Delegation</a></li><li class="chapter-item expanded affix "><li class="part-title">Upgrading</li><li class="chapter-item expanded "><a href="upgrade.html">Upgrading between Synapse Versions</a></li><li class="chapter-item expanded "><a href="MSC1711_certificates_FAQ.html" class="active">Upgrading from pre-Synapse 1.0</a></li><li class="chapter-item expanded affix "><li class="part-title">Usage</li><li class="chapter-item expanded "><a href="federate.html">Federation</a></li><li class="chapter-item expanded "><a href="usage/configuration/index.html">Configuration</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="usage/configuration/homeserver_sample_config.html">Homeserver Sample Config File</a></li><li class="chapter-item expanded "><a href="usage/configuration/logging_sample_config.html">Logging Sample Config File</a></li><li class="chapter-item expanded "><a href="structured_logging.html">Structured Logging</a></li><li class="chapter-item expanded "><a href="templates.html">Templates</a></li><li class="chapter-item expanded "><a href="usage/configuration/user_authentication/index.html">User Authentication</a></li><li><ol class="section"><li class="chapter-item expanded "><div>Single-Sign On</div></li><li><ol class="section"><li class="chapter-item expanded "><a href="openid.html">OpenID Connect</a></li><li class="chapter-item expanded "><div>SAML</div></li><li class="chapter-item expanded "><div>CAS</div></li><li class="chapter-item expanded "><a href="sso_mapping_providers.html">SSO Mapping Providers</a></li></ol></li><li class="chapter-item expanded "><a href="password_auth_providers.html">Password Auth Providers</a></li><li class="chapter-item expanded "><a href="jwt.html">JSON Web Tokens</a></li></ol></li><li class="chapter-item expanded "><a href="CAPTCHA_SETUP.html">Registration Captcha</a></li><li class="chapter-item expanded "><a href="application_services.html">Application Services</a></li><li class="chapter-item expanded "><a href="server_notices.html">Server Notices</a></li><li class="chapter-item expanded "><a href="consent_tracking.html">Consent Tracking</a></li><li class="chapter-item expanded "><a href="development/url_previews.html">URL Previews</a></li><li class="chapter-item expanded "><a href="user_directory.html">User Directory</a></li><li class="chapter-item expanded "><a href="message_retention_policies.html">Message Retention Policies</a></li><li class="chapter-item expanded "><a href="modules/index.html">Pluggable Modules</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="modules/writing_a_module.html">Writing a module</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="modules/spam_checker_callbacks.html">Spam checker callbacks</a></li><li class="chapter-item expanded "><a href="modules/third_party_rules_callbacks.html">Third-party rules callbacks</a></li><li class="chapter-item expanded "><a href="modules/presence_router_callbacks.html">Presence router callbacks</a></li><li class="chapter-item expanded "><a href="modules/account_validity_callbacks.html">Account validity callbacks</a></li><li class="chapter-item expanded "><a href="modules/porting_legacy_module.html">Porting a legacy module to the new in
</div>
<div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
</nav>
<div id="page-wrapper" class="page-wrapper">
<div class="page">
<div id="menu-bar-hover-placeholder"></div>
<div id="menu-bar" class="menu-bar sticky bordered">
<div class="left-buttons">
<button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
<i class="fa fa-bars"></i>
</button>
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
<i class="fa fa-paint-brush"></i>
</button>
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
<li role="none"><button role="menuitem" class="theme" id="light">Light (default)</button></li>
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
</ul>
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
<i class="fa fa-search"></i>
</button>
</div>
<h1 class="menu-title">Synapse</h1>
<div class="right-buttons">
<a href="print.html" title="Print this book" aria-label="Print this book">
<i id="print-button" class="fa fa-print"></i>
</a>
<a href="https://github.com/matrix-org/synapse" title="Git repository" aria-label="Git repository">
<i id="git-repository-button" class="fa fa-github"></i>
</a>
<a href="https://github.com/matrix-org/synapse/edit/develop/docs/MSC1711_certificates_FAQ.md" title="Suggest an edit" aria-label="Suggest an edit">
<i id="git-edit-button" class="fa fa-edit"></i>
</a>
</div>
</div>
<div id="search-wrapper" class="hidden">
<form id="searchbar-outer" class="searchbar-outer">
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
</form>
<div id="searchresults-outer" class="searchresults-outer hidden">
<div id="searchresults-header" class="searchresults-header"></div>
<ul id="searchresults">
</ul>
</div>
</div>
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
<script type="text/javascript">
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
});
</script>
<div id="content" class="content">
<main>
<!-- Page table of contents -->
<div class="sidetoc">
<nav class="pagetoc"></nav>
</div>
<h1 id="msc1711-certificates-faq"><a class="header" href="#msc1711-certificates-faq">MSC1711 Certificates FAQ</a></h1>
<h2 id="historical-note"><a class="header" href="#historical-note">Historical Note</a></h2>
<p>This document was originally written to guide server admins through the upgrade
path towards Synapse 1.0. Specifically,
<a href="https://github.com/matrix-org/matrix-doc/blob/main/proposals/1711-x509-for-federation.md">MSC1711</a>
required that all servers present valid TLS certificates on their federation
API. Admins were encouraged to achieve compliance from version 0.99.0 (released
in February 2019) ahead of version 1.0 (released June 2019) enforcing the
certificate checks.</p>
<p>Much of what follows is now outdated since most admins will have already
upgraded, however it may be of use to those with old installs returning to the
project.</p>
<p>If you are setting up a server from scratch you almost certainly should look at
the <a href="setup/installation.html">installation guide</a> instead.</p>
<h2 id="introduction"><a class="header" href="#introduction">Introduction</a></h2>
<p>The goal of Synapse 0.99.0 is to act as a stepping stone to Synapse 1.0.0. It
supports the r0.1 release of the server to server specification, but is
compatible with both the legacy Matrix federation behaviour (pre-r0.1) as well
as post-r0.1 behaviour, in order to allow for a smooth upgrade across the
federation.</p>
<p>The most important thing to know is that Synapse 1.0.0 will require a valid TLS
certificate on federation endpoints. Self signed certificates will not be
sufficient.</p>
<p>Synapse 0.99.0 makes it easy to configure TLS certificates and will
interoperate with both &gt;= 1.0.0 servers as well as existing servers yet to
upgrade.</p>
<p><strong>It is critical that all admins upgrade to 0.99.0 and configure a valid TLS
certificate.</strong> Admins will have 1 month to do so, after which 1.0.0 will be
released and those servers without a valid certificate will not longer be able
to federate with &gt;= 1.0.0 servers.</p>
<p>Full details on how to carry out this configuration change is given
<a href="#configuring-certificates-for-compatibility-with-synapse-100">below</a>. A
timeline and some frequently asked questions are also given below.</p>
<p>For more details and context on the release of the r0.1 Server/Server API and
imminent Matrix 1.0 release, you can also see our
<a href="https://matrix.org/blog/2019/02/04/matrix-at-fosdem-2019/">main talk from FOSDEM 2019</a>.</p>
<h2 id="contents"><a class="header" href="#contents">Contents</a></h2>
<ul>
<li>Timeline</li>
<li>Configuring certificates for compatibility with Synapse 1.0</li>
<li>FAQ
<ul>
<li>Synapse 0.99.0 has just been released, what do I need to do right now?</li>
<li>How do I upgrade?</li>
<li>What will happen if I do not set up a valid federation certificate
immediately?</li>
<li>What will happen if I do nothing at all?</li>
<li>When do I need a SRV record or .well-known URI?</li>
<li>Can I still use an SRV record?</li>
<li>I have created a .well-known URI. Do I still need an SRV record?</li>
<li>It used to work just fine, why are you breaking everything?</li>
<li>Can I manage my own certificates rather than having Synapse renew
certificates itself?</li>
<li>Do you still recommend against using a reverse proxy on the federation port?</li>
<li>Do I still need to give my TLS certificates to Synapse if I am using a
reverse proxy?</li>
<li>Do I need the same certificate for the client and federation port?</li>
<li>How do I tell Synapse to reload my keys/certificates after I replace them?</li>
</ul>
</li>
</ul>
<h2 id="timeline"><a class="header" href="#timeline">Timeline</a></h2>
<p><strong>5th Feb 2019 - Synapse 0.99.0 is released.</strong></p>
<p>All server admins are encouraged to upgrade.</p>
<p>0.99.0:</p>
<ul>
<li>
<p>provides support for ACME to make setting up Let's Encrypt certs easy, as
well as .well-known support.</p>
</li>
<li>
<p>does not enforce that a valid CA cert is present on the federation API, but
rather makes it easy to set one up.</p>
</li>
<li>
<p>provides support for .well-known</p>
</li>
</ul>
<p>Admins should upgrade and configure a valid CA cert. Homeservers that require a
.well-known entry (see below), should retain their SRV record and use it
alongside their .well-known record.</p>
<p><strong>10th June 2019 - Synapse 1.0.0 is released</strong></p>
<p>1.0.0 is scheduled for release on 10th June. In
accordance with the the <a href="https://matrix.org/docs/spec/server_server/r0.1.0.html">S2S spec</a>
1.0.0 will enforce certificate validity. This means that any homeserver without a
valid certificate after this point will no longer be able to federate with
1.0.0 servers.</p>
<h2 id="configuring-certificates-for-compatibility-with-synapse-100"><a class="header" href="#configuring-certificates-for-compatibility-with-synapse-100">Configuring certificates for compatibility with Synapse 1.0.0</a></h2>
<h3 id="if-you-do-not-currently-have-an-srv-record"><a class="header" href="#if-you-do-not-currently-have-an-srv-record">If you do not currently have an SRV record</a></h3>
<p>In this case, your <code>server_name</code> points to the host where your Synapse is
running. There is no need to create a <code>.well-known</code> URI or an SRV record, but
you will need to give Synapse a valid, signed, certificate.</p>
<h3 id="if-you-do-have-an-srv-record-currently"><a class="header" href="#if-you-do-have-an-srv-record-currently">If you do have an SRV record currently</a></h3>
<p>If you are using an SRV record, your matrix domain (<code>server_name</code>) may not
point to the same host that your Synapse is running on (the 'target
domain'). (If it does, you can follow the recommendation above; otherwise, read
on.)</p>
<p>Let's assume that your <code>server_name</code> is <code>example.com</code>, and your Synapse is
hosted at a target domain of <code>customer.example.net</code>. Currently you should have
an SRV record which looks like:</p>
<pre><code>_matrix._tcp.example.com. IN SRV 10 5 8000 customer.example.net.
</code></pre>
<p>In this situation, you have three choices for how to proceed:</p>
<h4 id="option-1-give-synapse-a-certificate-for-your-matrix-domain"><a class="header" href="#option-1-give-synapse-a-certificate-for-your-matrix-domain">Option 1: give Synapse a certificate for your matrix domain</a></h4>
<p>Synapse 1.0 will expect your server to present a TLS certificate for your
<code>server_name</code> (<code>example.com</code> in the above example). You can achieve this by acquiring a
certificate for the <code>server_name</code> yourself (for example, using <code>certbot</code>), and giving it
and the key to Synapse via <code>tls_certificate_path</code> and <code>tls_private_key_path</code>.</p>
<h4 id="option-2-run-synapse-behind-a-reverse-proxy"><a class="header" href="#option-2-run-synapse-behind-a-reverse-proxy">Option 2: run Synapse behind a reverse proxy</a></h4>
<p>If you have an existing reverse proxy set up with correct TLS certificates for
your domain, you can simply route all traffic through the reverse proxy by
updating the SRV record appropriately (or removing it, if the proxy listens on
8448).</p>
<p>See <a href="reverse_proxy.html">the reverse proxy documentation</a> for information on setting up a
reverse proxy.</p>
<h4 id="option-3-add-a-well-known-file-to-delegate-your-matrix-traffic"><a class="header" href="#option-3-add-a-well-known-file-to-delegate-your-matrix-traffic">Option 3: add a .well-known file to delegate your matrix traffic</a></h4>
<p>This will allow you to keep Synapse on a separate domain, without having to
give it a certificate for the matrix domain.</p>
<p>You can do this with a <code>.well-known</code> file as follows:</p>
<ol>
<li>
<p>Keep the SRV record in place - it is needed for backwards compatibility
with Synapse 0.34 and earlier.</p>
</li>
<li>
<p>Give Synapse a certificate corresponding to the target domain
(<code>customer.example.net</code> in the above example). You can do this by acquire a
certificate for the target domain and giving it to Synapse via <code>tls_certificate_path</code>
and <code>tls_private_key_path</code>.</p>
</li>
<li>
<p>Restart Synapse to ensure the new certificate is loaded.</p>
</li>
<li>
<p>Arrange for a <code>.well-known</code> file at
<code>https://&lt;server_name&gt;/.well-known/matrix/server</code> with contents:</p>
<pre><code class="language-json">{&quot;m.server&quot;: &quot;&lt;target server name&gt;&quot;}
</code></pre>
<p>where the target server name is resolved as usual (i.e. SRV lookup, falling
back to talking to port 8448).</p>
<p>In the above example, where synapse is listening on port 8000,
<code>https://example.com/.well-known/matrix/server</code> should have <code>m.server</code> set to one of:</p>
<ol>
<li>
<p><code>customer.example.net</code> ─ with a SRV record on
<code>_matrix._tcp.customer.example.com</code> pointing to port 8000, or:</p>
</li>
<li>
<p><code>customer.example.net</code> ─ updating synapse to listen on the default port
8448, or:</p>
</li>
<li>
<p><code>customer.example.net:8000</code> ─ ensuring that if there is a reverse proxy
on <code>customer.example.net:8000</code> it correctly handles HTTP requests with
Host header set to <code>customer.example.net:8000</code>.</p>
</li>
</ol>
</li>
</ol>
<h2 id="faq"><a class="header" href="#faq">FAQ</a></h2>
<h3 id="synapse-0990-has-just-been-released-what-do-i-need-to-do-right-now"><a class="header" href="#synapse-0990-has-just-been-released-what-do-i-need-to-do-right-now">Synapse 0.99.0 has just been released, what do I need to do right now?</a></h3>
<p>Upgrade as soon as you can in preparation for Synapse 1.0.0, and update your
TLS certificates as <a href="#configuring-certificates-for-compatibility-with-synapse-100">above</a>.</p>
<h3 id="what-will-happen-if-i-do-not-set-up-a-valid-federation-certificate-immediately"><a class="header" href="#what-will-happen-if-i-do-not-set-up-a-valid-federation-certificate-immediately">What will happen if I do not set up a valid federation certificate immediately?</a></h3>
<p>Nothing initially, but once 1.0.0 is in the wild it will not be possible to
federate with 1.0.0 servers.</p>
<h3 id="what-will-happen-if-i-do-nothing-at-all"><a class="header" href="#what-will-happen-if-i-do-nothing-at-all">What will happen if I do nothing at all?</a></h3>
<p>If the admin takes no action at all, and remains on a Synapse &lt; 0.99.0 then the
homeserver will be unable to federate with those who have implemented
.well-known. Then, as above, once the month upgrade window has expired the
homeserver will not be able to federate with any Synapse &gt;= 1.0.0</p>
<h3 id="when-do-i-need-a-srv-record-or-well-known-uri"><a class="header" href="#when-do-i-need-a-srv-record-or-well-known-uri">When do I need a SRV record or .well-known URI?</a></h3>
<p>If your homeserver listens on the default federation port (8448), and your
<code>server_name</code> points to the host that your homeserver runs on, you do not need an
SRV record or <code>.well-known/matrix/server</code> URI.</p>
<p>For instance, if you registered <code>example.com</code> and pointed its DNS A record at a
fresh Upcloud VPS or similar, you could install Synapse 0.99 on that host,
giving it a server_name of <code>example.com</code>, and it would automatically generate a
valid TLS certificate for you via Let's Encrypt and no SRV record or
<code>.well-known</code> URI would be needed.</p>
<p>This is the common case, although you can add an SRV record or
<code>.well-known/matrix/server</code> URI for completeness if you wish.</p>
<p><strong>However</strong>, if your server does not listen on port 8448, or if your <code>server_name</code>
does not point to the host that your homeserver runs on, you will need to let
other servers know how to find it.</p>
<p>In this case, you should see <a href="#if-you-do-have-an-srv-record-currently">&quot;If you do have an SRV record
currently&quot;</a> above.</p>
<h3 id="can-i-still-use-an-srv-record"><a class="header" href="#can-i-still-use-an-srv-record">Can I still use an SRV record?</a></h3>
<p>Firstly, if you didn't need an SRV record before (because your server is
listening on port 8448 of your server_name), you certainly don't need one now:
the defaults are still the same.</p>
<p>If you previously had an SRV record, you can keep using it provided you are
able to give Synapse a TLS certificate corresponding to your server name. For
example, suppose you had the following SRV record, which directs matrix traffic
for example.com to matrix.example.com:443:</p>
<pre><code>_matrix._tcp.example.com. IN SRV 10 5 443 matrix.example.com
</code></pre>
<p>In this case, Synapse must be given a certificate for example.com - or be
configured to acquire one from Let's Encrypt.</p>
<p>If you are unable to give Synapse a certificate for your server_name, you will
also need to use a .well-known URI instead. However, see also &quot;I have created a
.well-known URI. Do I still need an SRV record?&quot;.</p>
<h3 id="i-have-created-a-well-known-uri-do-i-still-need-an-srv-record"><a class="header" href="#i-have-created-a-well-known-uri-do-i-still-need-an-srv-record">I have created a .well-known URI. Do I still need an SRV record?</a></h3>
<p>As of Synapse 0.99, Synapse will first check for the existence of a <code>.well-known</code>
URI and follow any delegation it suggests. It will only then check for the
existence of an SRV record.</p>
<p>That means that the SRV record will often be redundant. However, you should
remember that there may still be older versions of Synapse in the federation
which do not understand <code>.well-known</code> URIs, so if you removed your SRV record you
would no longer be able to federate with them.</p>
<p>It is therefore best to leave the SRV record in place for now. Synapse 0.34 and
earlier will follow the SRV record (and not care about the invalid
certificate). Synapse 0.99 and later will follow the .well-known URI, with the
correct certificate chain.</p>
<h3 id="it-used-to-work-just-fine-why-are-you-breaking-everything"><a class="header" href="#it-used-to-work-just-fine-why-are-you-breaking-everything">It used to work just fine, why are you breaking everything?</a></h3>
<p>We have always wanted Matrix servers to be as easy to set up as possible, and
so back when we started federation in 2014 we didn't want admins to have to go
through the cumbersome process of buying a valid TLS certificate to run a
server. This was before Let's Encrypt came along and made getting a free and
valid TLS certificate straightforward. So instead, we adopted a system based on
<a href="https://en.wikipedia.org/wiki/Convergence_(SSL)">Perspectives</a>: an approach
where you check a set of &quot;notary servers&quot; (in practice, homeservers) to vouch
for the validity of a certificate rather than having it signed by a CA. As long
as enough different notaries agree on the certificate's validity, then it is
trusted.</p>
<p>However, in practice this has never worked properly. Most people only use the
default notary server (matrix.org), leading to inadvertent centralisation which
we want to eliminate. Meanwhile, we never implemented the full consensus
algorithm to query the servers participating in a room to determine consensus
on whether a given certificate is valid. This is fiddly to get right
(especially in face of sybil attacks), and we found ourselves questioning
whether it was worth the effort to finish the work and commit to maintaining a
secure certificate validation system as opposed to focusing on core Matrix
development.</p>
<p>Meanwhile, Let's Encrypt came along in 2016, and put the final nail in the
coffin of the Perspectives project (which was already pretty dead). So, the
Spec Core Team decided that a better approach would be to mandate valid TLS
certificates for federation alongside the rest of the Web. More details can be
found in
<a href="https://github.com/matrix-org/matrix-doc/blob/main/proposals/1711-x509-for-federation.md#background-the-failure-of-the-perspectives-approach">MSC1711</a>.</p>
<p>This results in a breaking change, which is disruptive, but absolutely critical
for the security model. However, the existence of Let's Encrypt as a trivial
way to replace the old self-signed certificates with valid CA-signed ones helps
smooth things over massively, especially as Synapse can now automate Let's
Encrypt certificate generation if needed.</p>
<h3 id="can-i-manage-my-own-certificates-rather-than-having-synapse-renew-certificates-itself"><a class="header" href="#can-i-manage-my-own-certificates-rather-than-having-synapse-renew-certificates-itself">Can I manage my own certificates rather than having Synapse renew certificates itself?</a></h3>
<p>Yes, you are welcome to manage your certificates yourself. Synapse will only
attempt to obtain certificates from Let's Encrypt if you configure it to do
so.The only requirement is that there is a valid TLS cert present for
federation end points.</p>
<h3 id="do-you-still-recommend-against-using-a-reverse-proxy-on-the-federation-port"><a class="header" href="#do-you-still-recommend-against-using-a-reverse-proxy-on-the-federation-port">Do you still recommend against using a reverse proxy on the federation port?</a></h3>
<p>We no longer actively recommend against using a reverse proxy. Many admins will
find it easier to direct federation traffic to a reverse proxy and manage their
own TLS certificates, and this is a supported configuration.</p>
<p>See <a href="reverse_proxy.html">the reverse proxy documentation</a> for information on setting up a
reverse proxy.</p>
<h3 id="do-i-still-need-to-give-my-tls-certificates-to-synapse-if-i-am-using-a-reverse-proxy"><a class="header" href="#do-i-still-need-to-give-my-tls-certificates-to-synapse-if-i-am-using-a-reverse-proxy">Do I still need to give my TLS certificates to Synapse if I am using a reverse proxy?</a></h3>
<p>Practically speaking, this is no longer necessary.</p>
<p>If you are using a reverse proxy for all of your TLS traffic, then you can set
<code>no_tls: True</code>. In that case, the only reason Synapse needs the certificate is
to populate a legacy 'tls_fingerprints' field in the federation API. This is
ignored by Synapse 0.99.0 and later, and the only time pre-0.99 Synapses will
check it is when attempting to fetch the server keys - and generally this is
delegated via <code>matrix.org</code>, which is on 0.99.0.</p>
<p>However, there is a bug in Synapse 0.99.0
<a href="https://github.com/matrix-org/synapse/issues/4554">4554</a> which prevents
Synapse from starting if you do not give it a TLS certificate. To work around
this, you can give it any TLS certificate at all. This will be fixed soon.</p>
<h3 id="do-i-need-the-same-certificate-for-the-client-and-federation-port"><a class="header" href="#do-i-need-the-same-certificate-for-the-client-and-federation-port">Do I need the same certificate for the client and federation port?</a></h3>
<p>No. There is nothing stopping you from using different certificates,
particularly if you are using a reverse proxy. However, Synapse will use the
same certificate on any ports where TLS is configured.</p>
<h3 id="how-do-i-tell-synapse-to-reload-my-keyscertificates-after-i-replace-them"><a class="header" href="#how-do-i-tell-synapse-to-reload-my-keyscertificates-after-i-replace-them">How do I tell Synapse to reload my keys/certificates after I replace them?</a></h3>
<p>Synapse will reload the keys and certificates when it receives a SIGHUP - for
example <code>kill -HUP $(cat homeserver.pid)</code>. Alternatively, simply restart
Synapse, though this will result in downtime while it restarts.</p>
</main>
<nav class="nav-wrapper" aria-label="Page navigation">
<!-- Mobile navigation buttons -->
<a rel="prev" href="upgrade.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
<a rel="next" href="federate.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
<i class="fa fa-angle-right"></i>
</a>
<div style="clear: both"></div>
</nav>
</div>
</div>
<nav class="nav-wide-wrapper" aria-label="Page navigation">
<a rel="prev" href="upgrade.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
<i class="fa fa-angle-left"></i>
</a>
<a rel="next" href="federate.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
<i class="fa fa-angle-right"></i>
</a>
</nav>
</div>
<script type="text/javascript">
window.playground_copyable = true;
</script>
<script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
<script src="mark.min.js" type="text/javascript" charset="utf-8"></script>
<script src="searcher.js" type="text/javascript" charset="utf-8"></script>
<script src="clipboard.min.js" type="text/javascript" charset="utf-8"></script>
<script src="highlight.js" type="text/javascript" charset="utf-8"></script>
<script src="book.js" type="text/javascript" charset="utf-8"></script>
<!-- Custom JS scripts -->
<script type="text/javascript" src="docs/website_files/table-of-contents.js"></script>
</body>
</html>