Fediversity/matrix/synapse/README.md

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Table of Contents

Installation and configuration of Synapse

Mind you: this an installation on Debian Linux (at least for now).

Start by installing the latest Synapse server, see the upstream documentation.

apt install -y lsb-release wget apt-transport-https build-essential python3-dev libffi-dev \
               python3-pip python3-setuptools sqlite3 \
               libssl-dev virtualenv libjpeg-dev libxslt1-dev libicu-dev

wget -O /usr/share/keyrings/matrix-org-archive-keyring.gpg https://packages.matrix.org/debian/matrix-org-archive-keyring.gpg

echo "deb [signed-by=/usr/share/keyrings/matrix-org-archive-keyring.gpg] https://packages.matrix.org/debian/ $(lsb_release -cs) main" |
    tee /etc/apt/sources.list.d/matrix-org.list

apt update
apt install matrix-synapse-py3

This leaves a very basic configuration in /etc/matrix-synapse/homeserver.yaml and two settings under /etc/conf.d. All other configuration items will also be configured with yaml-files in this directory.

Configure the domain you with to use in /etc/matrix-synapse/conf.d/server_name.yaml. What you configure here will also be the global part of your Matrix handles (the part after the colon). Also add the URL clients should connect to:

server_name: example.com
public_baseurl: https://matrix.example.com/

The public_baseurl will probably be different than the server_name, see also Delegation and DNS.

You now have a standard Matrix server that uses sqlite. You really don't want to use this in production, so probably want to replace this with PostgreSQL.

There are two different ways to configure Synapse, documented here:

We'll use Synapse, using the workers architecture to make it scalable, flexible and reusable.

Listeners

A fresh installation configures one listener, for both client and federation traffic. This listens on port 8008 on localhost (IPv4 and IPv6) and does not do TLS:

listeners:
  - port: 8008
    tls: false
    type: http
    x_forwarded: true
    bind_addresses: ['::1', '127.0.0.1']
    resources:
      - names: [client, federation]
        compress: false

Database

The default installation leaves you with an sqlite3 database. Nice for experimenting, but unsuitable for a production environment.

Here's how you setup PostgreSQL.

Once you've created a database and user in PostgreSQL, you configure Synapse to use it.

First delete (or comment out) the SQLITE datbase in homeserver.yaml:

#database:
#  name: sqlite3
#  args:
#    database: /var/lib/matrix-synapse/homeserver.db

Then create the database configuration for PostgreSQL in conf.d/database.yaml:

database:
  name: psycopg2
  args:
    user: synapse
    password: <password>
    dbname: synapse
    host: /var/run/postgresql
    cp_min: 5
    cp_max: 10

Note: you configure the directory where the UNIX socket file lives, not the actual file.

Of course, if you use localhost, you should configure it like this:

    host: localhost
    port: 5432

After changing the database, restart Synapse and check whether it can connect and create the tables it needs.

Create admin

Synapse doesn't create an admin account at install time, so you'll have to do that yourself.

You need to set a registration_shared_secret for this, set that in conf.d/keys.yaml like this:

registration_shared_secret: xxxx

You can create such a key by running pwgen -csn 52 1. Restart Synapse after setting this key.

Now create an admin user. Login and issue this command:

register_new_matrix_user -u admin -a -c /etc/matrix-synapse/conf.d/keys.yaml

This will ask for a password, choose a safe one.

Logging

Logging is configured in log.yaml. Some logging should go to systemd, the more specific logging to Synapse's own logfile(s).

This part is yet to be completed.

Delegation and DNS

If you run your server under a different FQDN than just the domain name you want to use, you need to delegate: point from your domain to the server.

Example. You want to use example.com for your domain, but your server is called matrix.example.com. To make that work, you need to serve 2 bits of JSON-code on example.com to point clients and servers to the correct machine: matrix.example.com.

Pointing servers to the correct server is done by publishing this bit of JSON-code under https://example.com/.well-known/matrix/server:

{
  "m.homeserver": {"base_url": "https://matrix.example.com"},
  "org.matrix.msc3575.proxy": {"url": "https://matrix.example.com"}
}

Pointing clients to the correct server needs this at https://example.com/.well-known/matrix/client:

{
  "m.server": "matrix.example.com"
}

Very important: both names (example.com and matrix.example.com) must be A and/or AAAA records in DNS, not CNAME.

See nginx for details about how to publish this data.

Blacklists

You don't want Synapse to try to contact certain IP-addresses, especially not those that are unroutable or for special uses. Add these addresses to ip_range_blacklist, in conf.d/ip_range_blacklist.yaml:

ip_range_blacklist:
  - '127.0.0.0/8'
  - '10.0.0.0/8'
  - '172.16.0.0/12'
  - '192.168.0.0/16'
  - '100.64.0.0/10'
  - '192.0.0.0/24'
  - '169.254.0.0/16'
  - '192.88.99.0/24'
  - '198.18.0.0/15'
  - '192.0.2.0/24'
  - '198.51.100.0/24'
  - '203.0.113.0/24'
  - '224.0.0.0/4'
  - '::1/128'
  - 'fe80::/10'
  - 'fc00::/7'
  - '2001:db8::/32'
  - 'ff00::/8'
  - 'fec0::/10'

You want to add addresses of malicious or otherwise unwanted machines to this list too. See Synapse's documentation for more information.

E-mail

Synapse should probably be able to send out e-mails; notifications for those who want that, and password reset for those who need one.

You configure this under the section email (yes, really).

First of all, you need an SMTP-server that is configured to send e-mail for your domain. Configuring that is out of scope, we'll assume we can use the server smtp.example.com.

Configure this in conf.d/email.yaml:

email:
  smtp_host: smtp.example.com
  smtp_port: 465
  smtp_user: matrix@example.com
  smtp_pass: SuperSecretPassword
  force_tls: true
  notif_from: "Your Matrix server <matrix@example.com>"

This configures an SMTP-connection with SSL (port 465, force_tls). See Matrix' email documentation for more information.

Media store

Files and avatars need to be stored somewhere, we configure these options in conf.d/mediastore.yaml:

media_store_path: /var/lib/matrix-synapse/media
enable_authenticated_media: true
max_upload_size: 50M
url_preview_enabled: true
url_preview_ip_range_blacklist:
  - '127.0.0.0/8'
  - '10.0.0.0/8'
  - '172.16.0.0/12'
  - '192.168.0.0/16'
  - '100.64.0.0/10'
  - '192.0.0.0/24'
  - '169.254.0.0/16'
  - '192.88.99.0/24'
  - '198.18.0.0/15'
  - '192.0.2.0/24'
  - '198.51.100.0/24'
  - '203.0.113.0/24'
  - '224.0.0.0/4'
  - '::1/128'
  - 'fe80::/10'
  - 'fc00::/7'
  - '2001:db8::/32'
  - 'ff00::/8'
  - 'fec0::/10'

These are a few sane (?) defaults, check Matrix' documentation for many more options.

Homeserver blocking

This is a series of options that can be used to block and/or limit users. The whole list of options can be found in Matrix' documentation, we're going to pick out a few useful ones.

Let's configure these options in conf.d/homeserver_blocking.yaml.

admin_contact: matrixadmin@example.com
mau_stats_only: true
max_avatar_size: 2M
allowed_avatar_mimetypes:
  - "image/png"
  - "image/jpeg"
  - "image/gif"
forgotten_room_retention_period: 7d