Create an XMPP server with Prosody compatible with Conversations and Movim

Recently I set up an XMPP server (and a Matrix one, too) for my personal use and for friends if they want one; made one for EL ELE EME, for example. So, here are the notes on how I set up the server that is compatible with the Conversations app and the Movim social network. You can see my addresses in contact and the XMPP compliance/score of the server.

One of the best resources I found that helped me a lot was Installing and Configuring Prosody XMPP Server on Debian 9, and of course the Arch Wiki and the oficial documentation.

As with my other entries, this is under a server running Arch Linux, with the Nginx web server and Certbot certificates. And all commands here are executed as root (unless specified otherwise)

Prerequisites

Same as with my other entries (website, mail and git) plus:

Prosody

Prosody is an implementation of the XMPP protocol that is flexible and extensible.

Install the prosody package (with optional dependencies) and the mercurial package:

pacman -S prosody, mercurial, lua52-sec, lua52-dbi, lua52-zlib

We need mercurial to be able to download and update the extra modules needed to make the server compliant with conversations.im and mov.im. Go to /var/lib/prosody, clone the latest Prosody modules repository and prepare the directories:

cd /var/lib/prosody
hg clone https://hg.prosody.im/prosody-modules modules-available
mkdir modules-enabled

You can see that I follow a similar approach that I used with Nginx and the server configuration, where I have all the modules available in a directory, and make a symlink to another to keep track of what is being used. You can update the repository by running hg pull --update while inside the modules-available directory (similar to Git).

Make symbolic links to the following modules:

ln -s /var/lib/prosody/modules-available/MODULE_NAME /var/lib/prosody/modules-enabled/
...

And add other modules if needed, but these work for the apps that I mentioned. You should also change the permissions for these files:

chown -R prosody:prosody /var/lib/prosody

Now, configure the server by editing the /etc/prosody/prosody.cfg.lua file. It’s a bit tricky to configure, so here is my configuration file (lines starting with -- are comments). Make sure to change according to your domain, and maybe preferences. Read each line and each comment to know what’s going on, It’s easier to explain it with comments in the file itself than strip it in a lot of pieces.

And also, note that the configuration file has a “global” section and a per “virtual server”/”component” section, basically everything above all the VirtualServer/Component sections are global, and bellow each VirtualServer/Component, corresponds to that section.

-- important for systemd
daemonize = true
pidfile = "/run/prosody/prosody.pid"

-- or your account, not that this is an xmpp jid, not email
admins = { "admin@your.domain" }

contact_info = {
    abuse = { "mailto:abuse@your.domain", "xmpp:abuse@your.domain" };
    admin = { "mailto:admin@your.domain", "xmpp:admin@your.domain" };
    admin = { "mailto:feedback@your.domain", "xmpp:feedback@your.domain" };
    security = { "mailto:security@your.domain" };
    support = { "mailto:support@your.domain", "xmpp:support@muc.your.domain" };
}

-- so prosody look up the plugins we added
plugin_paths = { "/var/lib/prosody/modules-enabled" }

modules_enabled = {
    -- Generally required
        "roster"; -- Allow users to have a roster. Recommended ;)
        "saslauth"; -- Authentication for clients and servers. Recommended if you want to log in.
        "tls"; -- Add support for secure TLS on c2s/s2s connections
        "dialback"; -- s2s dialback support
        "disco"; -- Service discovery
    -- Not essential, but recommended
        "carbons"; -- Keep multiple clients in sync
        "pep"; -- Enables users to publish their avatar, mood, activity, playing music and more
        "private"; -- Private XML storage (for room bookmarks, etc.)
        "blocklist"; -- Allow users to block communications with other users
        "vcard4"; -- User profiles (stored in PEP)
        "vcard_legacy"; -- Conversion between legacy vCard and PEP Avatar, vcard
        "limits"; -- Enable bandwidth limiting for XMPP connections
    -- Nice to have
        "version"; -- Replies to server version requests
        "uptime"; -- Report how long server has been running
        "time"; -- Let others know the time here on this server
        "ping"; -- Replies to XMPP pings with pongs
        "register"; -- Allow users to register on this server using a client and change passwords
        "mam"; -- Store messages in an archive and allow users to access it
        "csi_simple"; -- Simple Mobile optimizations
    -- Admin interfaces
        "admin_adhoc"; -- Allows administration via an XMPP client that supports ad-hoc commands
        --"admin_telnet"; -- Opens telnet console interface on localhost port 5582
    -- HTTP modules
        "http"; -- Explicitly enable http server.
        "bosh"; -- Enable BOSH clients, aka "Jabber over HTTP"
        "websocket"; -- XMPP over WebSockets
        "http_files"; -- Serve static files from a directory over HTTP
    -- Other specific functionality
        "groups"; -- Shared roster support
        "server_contact_info"; -- Publish contact information for this service
        "announce"; -- Send announcement to all online users
        "welcome"; -- Welcome users who register accounts
        "watchregistrations"; -- Alert admins of registrations
        "motd"; -- Send a message to users when they log in
        --"legacyauth"; -- Legacy authentication. Only used by some old clients and bots.
        --"s2s_bidi"; -- not yet implemented, have to wait for v0.12
        "bookmarks";
        "checkcerts";
        "cloud_notify";
        "csi_battery_saver";
        "default_bookmarks";
        "http_avatar";
        "idlecompat";
        "presence_cache";
        "smacks";
        "strict_https";
        --"pep_vcard_avatar"; -- not compatible with this version of pep, wait for v0.12
        "watchuntrusted";
        "webpresence";
        "external_services";
    }

-- only if you want to disable some modules
modules_disabled = {
    -- "offline"; -- Store offline messages
    -- "c2s"; -- Handle client connections
    -- "s2s"; -- Handle server-to-server connections
    -- "posix"; -- POSIX functionality, sends server to background, enables syslog, etc.
}

external_services = {
    {
        type = "stun",
        transport = "udp",
        host = "proxy.your.domain",
        port = 3478
    }, {
        type = "turn",
        transport = "udp",
        host = "proxy.your.domain",
        port = 3478,
        -- you could decide this now or come back later when you install coturn
        secret = "YOUR SUPER SECRET TURN PASSWORD"
    }
}

--- general global configuration
http_ports = { 5280 }
http_interfaces = { "*", "::" }

https_ports = { 5281 }
https_interfaces = { "*", "::" }

proxy65_ports = { 5000 }
proxy65_interfaces = { "*", "::" }

http_default_host = "xmpp.your.domain"
http_external_url = "https://xmpp.your.domain/"
-- or if you want to have it somewhere else, change this
https_certificate = "/etc/prosody/certs/xmpp.your.domain.crt"

hsts_header = "max-age=31556952"

cross_domain_bosh = true
--consider_bosh_secure = true
cross_domain_websocket = true
--consider_websocket_secure = true

trusted_proxies = { "127.0.0.1", "::1", "192.169.1.1" }

pep_max_items = 10000

-- this is disabled by default, and I keep it like this, depends on you
--allow_registration = true

-- you might want this options as they are
c2s_require_encryption = true
s2s_require_encryption = true
s2s_secure_auth = false
--s2s_insecure_domains = { "insecure.example" }
--s2s_secure_domains = { "jabber.org" }

-- where the certificates are stored (/etc/prosody/certs by default)
certificates = "certs"
checkcerts_notify = 7 -- ( in days )

-- rate limits on connections to the server, these are my personal settings, because by default they were limited to something like 30kb/s
limits = {
    c2s = {
        rate = "2000kb/s";
    };
    s2sin = {
        rate = "5000kb/s";
    };
    s2sout = {
        rate = "5000kb/s";
    };
}

-- again, this could be yourself, it is a jid
unlimited_jids = { "admin@your.domain" }

authentication = "internal_hashed"

-- if you don't want to use sql, change it to internal and comment the second line
-- since this is optional, i won't describe how to setup mysql or setup the user/database, that would be out of the scope for this entry
storage = "sql"
sql = { driver = "MySQL", database = "prosody", username = "prosody", password = "PROSODY USER SECRET PASSWORD", host = "localhost" }

archive_expires_after = "4w" -- configure message archive
max_archive_query_results = 20;
mam_smart_enable = true
default_archive_policy = "roster" -- archive only messages from users who are in your roster

-- normally you would like at least one log file of certain level, but I keep all of them, the default is only the info = "*syslog" one
log = {
    info = "*syslog";
    warn = "prosody.warn";
    error = "prosody.err";
    debug = "prosody.debug";
    -- "*console"; -- Needs daemonize=false
}

-- cloud_notify
push_notification_with_body = false -- Whether or not to send the message body to remote pubsub node
push_notification_with_sender = false -- Whether or not to send the message sender to remote pubsub node
push_max_errors = 5 -- persistent push errors are tolerated before notifications for the identifier in question are disabled
push_max_devices = 5 -- number of allowed devices per user

-- by default every user on this server will join these muc rooms
default_bookmarks = {
    { jid = "room@muc.your.domain", name = "The Room" };
    { jid = "support@muc.your.domain", name = "Support Room" };
}

-- could be your jid
untrusted_fail_watchers = { "admin@your.domain" }
untrusted_fail_notification = "Establishing a secure connection from $from_host to $to_host failed. Certificate hash: $sha1. $errors"

----------- Virtual hosts -----------
VirtualHost "your.domain"
    name = "Prosody"
    http_host = "xmpp.your.domain"

disco_items = {
    { "your.domain", "Prosody" };
    { "muc.your.domain", "MUC Service" };
    { "pubsub.your.domain", "Pubsub Service" };
    { "proxy.your.domain", "SOCKS5 Bytestreams Service" };
    { "vjud.your.domain", "User Directory" };
}


-- Multi-user chat
Component "muc.your.domain" "muc"
    name = "MUC Service"
    modules_enabled = {
        --"bob"; -- not compatible with this version of Prosody
        "muc_limits";
        "muc_mam"; -- message archive in muc, again, a placeholder
        "muc_mam_hints";
        "muc_mention_notifications";
        "vcard_muc";
    }

    restrict_room_creation = false

    muc_log_by_default = true
    muc_log_presences = false
    log_all_rooms = false
    muc_log_expires_after = "1w"
    muc_log_cleanup_interval = 4 * 60 * 60


-- Upload
Component "xmpp.your.domain" "http_upload"
    name = "Upload Service"
    http_host= "xmpp.your.domain"
    -- you might want to change this, these are numbers in bytes, so 10MB and 100MB respectively
    http_upload_file_size_limit = 1024*1024*10
    http_upload_quota = 1024*1024*100


-- Pubsub
Component "pubsub.your.domain" "pubsub"
    name = "Pubsub Service"
    pubsub_max_items = 10000
    modules_enabled = {
        "pubsub_feeds";
        "pubsub_text_interface";
    }

    -- personally i don't have any feeds configured
    feeds = {
        -- The part before = is used as PubSub node
        --planet_jabber = "http://planet.jabber.org/atom.xml";
        --prosody_blog = "http://blog.prosody.im/feed/atom.xml";
    }


-- Proxy
Component "proxy.your.domain" "proxy65"
    name = "SOCKS5 Bytestreams Service"
    proxy65_address = "proxy.your.domain"


-- Vjud, user directory
Component "vjud.your.domain" "vjud"
    name = "User Directory"
    vjud_mode = "opt-in"

You HAVE to read all of the configuration file, because there are a lot of things that you need to change to make it work with your server/domain. Test the configuration file with:

luac5.2 -p /etc/prosody/prosody.cfg.lua

Notice that by default prosody will look up certificates that look like sub.your.domain, but if you get the certificates like I do, you’ll have a single certificate for all subdomains, and by default it is in /etc/letsencrypt/live, which has some strict permissions. So, to import it you can run:

prosodyctl --root cert import /etc/letsencrypt/live

Ignore the complaining about not finding the subdomain certificates and note that you will have to run that command on each certificate renewal, to automate this, add the --deploy-hook flag to your automated Certbot renewal system; for me it’s a systemd timer with the following certbot.service:

[Unit]
Description=Let's Encrypt renewal

[Service]
Type=oneshot
ExecStart=/usr/bin/certbot renew --quiet --agree-tos --deploy-hook "systemctl reload nginx.service && prosodyctl --root cert import /etc/letsencrypt/live"

And if you don’t have it already, the certbot.timer:

[Unit]
Description=Twice daily renewal of Let's Encrypt's certificates

[Timer]
OnCalendar=0/12:00:00
RandomizedDelaySec=1h
Persistent=true

[Install]
WantedBy=timers.target

Also, go to the certs directory and make the appropriate symbolic links:

cd /etc/prosody/certs
ln -s your.domain.crt SUBDOMAIN.your.domain.crt
ln -s your.domain.key SUBDOMAIN.your.domain.key
...

That’s basically all the configuration that needs Prosody itself, but we still have to configure Nginx and Coturn before starting/enabling the prosody service.

Nginx configuration file

Since this is not an ordinary configuration file I’m going to describe this too. Your prosody.conf file should have the following location blocks under the main server block (the one that listens to HTTPS):

# HTTPS server block
server {
    root /var/www/prosody/;
    server_name xmpp.luevano.xyz muc.luevano.xyz pubsub.luevano.xyz vjud.luevano.xyz proxy.luevano.xyz;
    index index.html;

    # for extra https discovery (XEP-0256)
    location /.well-known/acme-challenge {
        allow all;
    }

    # bosh specific
    location /http-bind {
        proxy_pass  https://localhost:5281/http-bind;

        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_buffering off;
        tcp_nodelay on;
    }

    # websocket specific
    location /xmpp-websocket {
        proxy_pass https://localhost:5281/xmpp-websocket;

        proxy_http_version 1.1;
        proxy_set_header Connection "Upgrade";
        proxy_set_header Upgrade $http_upgrade;

        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_read_timeout 900s;
    }

    # general proxy
    location / {
        proxy_pass https://localhost:5281;

        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Real-IP $remote_addr;
    }
    ...
    # Certbot stuff
}
# HTTP server block (the one that certbot creates)
server {
    ...
}

Also, you need to add the following to your actual your.domain (this cannot be a subdomain) configuration file:

server {
    ...
    location /.well-known/host-meta {
        default_type 'application/xrd+xml';
        add_header Access-Control-Allow-Origin '*' always;
    }

    location /.well-known/host-meta.json {
        default_type 'application/jrd+json';
        add_header Access-Control-Allow-Origin '*' always;
    }
    ...
}

And you will need the following host-meta and host-meta.json files inside the .well-known/acme-challenge directory for your.domain (following my nomenclature: /var/www/yourdomaindir/.well-known/acme-challenge/).

For host-meta file:

<?xml version='1.0' encoding='utf-8'?>
<XRD xmlns='http://docs.oasis-open.org/ns/xri/xrd-1.0'>
    <Link rel="urn:xmpp:alt-connections:xbosh"
        href="https://xmpp.your.domain:5281/http-bind" />
    <Link rel="urn:xmpp:alt-connections:websocket"
        href="wss://xmpp.your.domain:5281/xmpp-websocket" />
</XRD>

And host-meta.json file:

{
    "links": [
        {
            "rel": "urn:xmpp:alt-connections:xbosh",
                "href": "https://xmpp.your.domain:5281/http-bind"
        },
        {
            "rel": "urn:xmpp:alt-connections:websocket",
                "href": "wss://xmpp.your.domain:5281/xmpp-websocket"
        }
    ]
}

Remember to have your prosody.conf file symlinked (or discoverable by Nginx) to the sites-enabled directory. You can now restart your nginx service (and test the configuration, optionally):

nginx -t
systemctl restart nginx.service

Coturn

Coturn is the implementation of TURN and STUN server, which in general is for (at least in the XMPP world) voice support and external service discovery.

Install the coturn package:

pacman -S coturn

You can modify the configuration file (located at /etc/turnserver/turnserver.conf) as desired, but at least you need to make the following changes (uncomment or edit):

use-auth-secret
realm=proxy.your.domain
static-auth-secret=YOUR SUPER SECRET TURN PASSWORD

I’m sure there is more configuration to be made, like using SQL to store data and whatnot, but for now this is enough for me. Note that you may not have some functionality that’s needed to create dynamic users to use the TURN server, and to be honest I haven’t tested this since I don’t use this feature in my XMPP clients, but if it doesn’t work, or you know of an error or missing configuration don’t hesitate to contact me.

Start/enable the turnserver service:

systemctl start turnserver.service
systemctl enable turnserver.service

You can test if your TURN server works at Trickle ICE. You may need to add a user in the turnserver.conf to test this.

Wrapping up

At this point you should have a working XMPP server, start/enable the prosody service now:

systemctl start prosody.service
systemctl enable prosody.service

And you can add your first user with the prosodyctl command (it will prompt you to add a password):

prosodyctl adduser user@your.domain

You may want to add a compliance user, so you can check if your server is set up correctly. To do so, go to XMPP Compliance Tester and enter the compliance user credentials. It should have similar compliance score to mine:

Additionally, you can test the security of your server in IM Observatory, here you only need to specify your domain.name (not xmpp.domain.name, if you set up the SRV DNS records correctly). Again, it should have a similar score to mine:

xmpp.net score

You can now log in into your XMPP client of choice, if it asks for the server it should be xmpp.your.domain (or your.domain for some clients) and your login credentials you@your.domain and the password you chose (which you can change in most clients).

That’s it, send me a message david@luevano.xyz if you were able to set up the server successfully.

Index Previous

By David Luévano

Created: Wed, Jun 09, 2021 @ 05:24 UTC

Modified: Thu, Jun 10, 2021 @ 04:42 UTC

Tags: english, server, tools, tutorial