doveauth-http: deploying HTTP route for account creation

- allow higher smtp connection limit

README.md

@@ -81,10 +81,11 @@ comprised of minimal setups of
 
 as well as two custom services that are integrated with these two: 
 
-- `chatmaild/src/chatmaild/dictproxy.py` implements 
+- `chatmaild/src/chatmaild/doveauth.py` implements
   create-on-login account creation semantics and is used
   by Dovecot during login authentication and by Postfix
-  which in turn uses Dovecot SASL to authenticate users
+  which in turn uses [Dovecot SASL](https://doc.dovecot.org/configuration_manual/authentication/dict/#complete-example-for-authenticating-via-a-unix-socket)
+  to authenticate users
   to send mails for them. 
 
 - `chatmaild/src/chatmaild/filtermail.py` prevents 

chatmaild/pyproject.toml

@@ -6,15 +6,21 @@ build-backend = "setuptools.build_meta"
 name = "chatmaild"
 version = "0.1"
 dependencies = [
-  "aiosmtpd"
+  "aiosmtpd",
+  "flask",
+  "gunicorn",
 ]
 
 [project.scripts]
-doveauth-dictproxy = "chatmaild.dictproxy:main"
+doveauth = "chatmaild.doveauth:main"
+doveauth-http = "chatmaild.web:main"
 filtermail = "chatmaild.filtermail:main"
 
 [tool.pytest.ini_options]
 addopts = "-v -ra --strict-markers"
+log_format = "%(asctime)s %(levelname)s %(message)s"
+log_date_format = "%Y-%m-%d %H:%M:%S"
+log_level = "INFO"
 
 [tool.tox]
 legacy_tox_ini = """

chatmaild/src/chatmaild/doveauth-http.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=HTTP endpoint for creating chatmail accounts
+
+[Service]
+ExecStart=/usr/local/bin/gunicorn --timeout 60 -b :3691 -w 1 chatmaild.web:main
+Restart=always
+RestartSec=30
+
+[Install]
+WantedBy=multi-user.target

chatmaild/src/chatmaild/doveauth.py

@@ -3,7 +3,6 @@ import os
 import time
 import sys
 import json
-import crypt
 from socketserver import (
     UnixStreamServer,
     StreamRequestHandler,
@@ -12,39 +11,7 @@ from socketserver import (
 import pwd
 
 from .database import Database
-
+from .util import is_allowed_to_create, encrypt_password, get_mail_domain
-NOCREATE_FILE = "/etc/chatmail-nocreate"
-
-
-def encrypt_password(password: str):
-    # https://doc.dovecot.org/configuration_manual/authentication/password_schemes/
-    passhash = crypt.crypt(password, crypt.METHOD_SHA512)
-    return "{SHA512-CRYPT}" + passhash
-
-
-def is_allowed_to_create(user, cleartext_password) -> bool:
-    """Return True if user and password are admissable."""
-    if os.path.exists(NOCREATE_FILE):
-        logging.warning(f"blocked account creation because {NOCREATE_FILE!r} exists.")
-        return False
-
-    if len(cleartext_password) < 10:
-        logging.warning("Password needs to be at least 10 characters long")
-        return False
-
-    parts = user.split("@")
-    if len(parts) != 2:
-        logging.warning(f"user {user!r} is not a proper e-mail address")
-        return False
-    localpart, domain = parts
-
-    if domain == "nine.testrun.org":
-        # nine.testrun.org policy, username has to be exactly nine chars
-        if len(localpart) != 9:
-            logging.warning(f"localpart {localpart!r} has not exactly nine chars")
-            return False
-
-    return True
 
 
 def get_user_data(db, user):
@@ -116,26 +83,31 @@ def handle_dovecot_request(msg, db, mail_domain):
 
 
 class ThreadedUnixStreamServer(ThreadingMixIn, UnixStreamServer):
-    pass
+    request_queue_size = 100
 
 
 def main():
     socket = sys.argv[1]
     passwd_entry = pwd.getpwnam(sys.argv[2])
     db = Database(sys.argv[3])
-    with open("/etc/mailname", "r") as fp:
+    mail_domain = get_mail_domain()
-        mail_domain = fp.read().strip()
 
     class Handler(StreamRequestHandler):
         def handle(self):
-            while True:
+            try:
-                msg = self.rfile.readline().strip().decode()
+                while True:
-                if not msg:
+                    msg = self.rfile.readline().strip().decode()
-                    break
+                    if not msg:
-                res = handle_dovecot_request(msg, db, mail_domain)
+                        break
-                if res:
+                    res = handle_dovecot_request(msg, db, mail_domain)
-                    self.wfile.write(res.encode("ascii"))
+                    if res:
-                    self.wfile.flush()
+                        self.wfile.write(res.encode("ascii"))
+                        self.wfile.flush()
+                    else:
+                        logging.warn("request had no answer: %r", msg)
+            except Exception:
+                logging.exception("Exception in the handler")
+                raise
 
     try:
         os.unlink(socket)

chatmaild/src/chatmaild/doveauth.service

@@ -2,7 +2,7 @@
 Description=Dict authentication proxy for dovecot
 
 [Service]
-ExecStart=/usr/local/bin/doveauth-dictproxy /run/dovecot/doveauth.socket vmail /home/vmail/passdb.sqlite
+ExecStart=/usr/local/bin/doveauth /run/dovecot/doveauth.socket vmail /home/vmail/passdb.sqlite
 Restart=always
 RestartSec=30
 

chatmaild/src/chatmaild/filtermail.py

@@ -149,7 +149,7 @@ class SendRateLimiter:
 def main():
     args = sys.argv[1:]
     assert len(args) == 1
-    logging.basicConfig(level=logging.INFO)
+    logging.basicConfig(level=logging.WARN)
     loop = asyncio.new_event_loop()
     asyncio.set_event_loop(loop)
     task = asyncmain_beforequeue(port=int(args[0]))

chatmaild/src/chatmaild/util.py

@@ -0,0 +1,56 @@
+import base64
+import random
+import logging
+import os
+import crypt
+
+
+NOCREATE_FILE = "/etc/chatmail-nocreate"
+
+
+def is_allowed_to_create(user, cleartext_password) -> bool:
+    """Return True if user and password are admissable."""
+    if os.path.exists(NOCREATE_FILE):
+        logging.warning(f"blocked account creation because {NOCREATE_FILE!r} exists.")
+        return False
+
+    if len(cleartext_password) < 10:
+        logging.warning("Password needs to be at least 10 characters long")
+        return False
+
+    parts = user.split("@")
+    if len(parts) != 2:
+        logging.warning(f"user {user!r} is not a proper e-mail address")
+        return False
+    localpart, domain = parts
+
+    if domain == "nine.testrun.org":
+        # nine.testrun.org policy, username has to be exactly nine chars
+        if len(localpart) != 9:
+            logging.warning(f"localpart {localpart!r} has not exactly nine chars")
+            return False
+
+    return True
+
+
+def gen_password():
+    with open("/dev/urandom", "rb") as f:
+        s = f.read(21)
+    return base64.b64encode(s).decode("ascii")[:12]
+
+
+def encrypt_password(password: str):
+    # https://doc.dovecot.org/configuration_manual/authentication/password_schemes/
+    passhash = crypt.crypt(password, crypt.METHOD_SHA512)
+    return "{SHA512-CRYPT}" + passhash
+
+
+def get_mail_domain():
+    with open("/etc/mailname", "r") as fp:
+        return fp.read().strip()
+
+
+def get_valid_email_addr(length=9, chars="2345789acdefghjkmnpqrstuvwxyz"):
+    localpart = "".join(random.choice(chars) for i in range(length))
+    mail_domain = get_mail_domain()
+    return f"{localpart}@{mail_domain}"

chatmaild/src/chatmaild/web.py

@@ -0,0 +1,48 @@
+from flask import Flask, jsonify, request
+import time
+import os
+
+from database import Database
+from util import gen_password, get_valid_email_addr, encrypt_password
+from doveauth import get_user_data
+
+
+def create_app_from_db_path(db_path=None):
+    db = Database(db_path)
+    return create_app_from_db(db)
+
+
+def create_app_from_db(db):
+    app = Flask("chatmaild-http")
+    app.db = db
+
+    @app.route("/", methods=["POST"])
+    def new_email():
+        for i in range(10):
+            addr = get_valid_email_addr()
+            if not get_user_data(db, addr):
+                cleartext_password = gen_password()
+                encrypted_password = encrypt_password(cleartext_password)
+                q = """INSERT INTO users (addr, password, last_login)
+                       VALUES (?, ?, ?)"""
+                with db.write_transaction() as conn:
+                    conn.execute(q, (addr, encrypted_password, int(time.time())))
+                return jsonify(
+                    email=addr,
+                    password=cleartext_password,
+                )
+        return jsonify(
+            type="error",
+            status_code=409,
+            reason="all 10 email addresses we tried are taken"
+        )
+
+    return app
+
+
+def main():
+    """(debugging-only!) serve http account creation Web API on localhost"""
+    db_path = os.getenv("CHATMAIL_DATABASE", "/home/vmail/passdb.sqlite")
+    app = create_app_from_db_path(db_path)
+    if __name__ == "__main__":
+        app.run(debug=True, host="localhost", port=3691)

deploy-chatmail/src/deploy_chatmail/__init__.py

@@ -7,6 +7,7 @@ from pathlib import Path
 from pyinfra import host
 from pyinfra.operations import apt, files, server, systemd
 from pyinfra.facts.files import File
+from pyinfra.facts.systemd import SystemdEnabled
 from .acmetool import deploy_acmetool
 
 
@@ -24,8 +25,8 @@ def _install_chatmaild() -> None:
         )
 
         apt.packages(
-            name="apt install python3-aiosmtpd",
+            name="apt install python3-aiosmtpd python3-pip python3-venv",
-            packages=["python3-aiosmtpd", "python3-pip"],
+            packages=["python3-aiosmtpd", "python3-pip", "python3-venv"],
         )
 
         # --no-deps because aiosmtplib is installed with `apt`.
@@ -34,8 +35,18 @@ def _install_chatmaild() -> None:
             commands=[f"pip install --break-system-packages {remote_path}"],
         )
 
+        # disable legacy doveauth-dictproxy.service
+        if host.get_fact(SystemdEnabled).get("doveauth-dictproxy.service"):
+            systemd.service(
+                name="Disable legacy doveauth-dictproxy.service",
+                service="doveauth-dictproxy.service",
+                running=False,
+                enabled=False,
+            )
+
         for fn in (
-            "doveauth-dictproxy",
+            "doveauth",
+            "doveauth-http",
             "filtermail",
         ):
             files.put(
@@ -123,6 +134,44 @@ def _configure_opendkim(domain: str, dkim_selector: str) -> bool:
     return need_restart
 
 
+def _install_mta_sts_daemon() -> bool:
+    need_restart = False
+
+    config = files.put(
+        name="upload postfix-mta-sts-resolver config",
+        src=importlib.resources.files(__package__).joinpath(
+            "postfix/mta-sts-daemon.yml"
+        ),
+        dest="/etc/mta-sts-daemon.yml",
+        user="root",
+        group="root",
+        mode="644",
+    )
+    need_restart |= config.changed
+
+    server.shell(
+        name="install postfix-mta-sts-resolver with pip",
+        commands=[
+            "python3 -m venv /usr/local/lib/postfix-mta-sts-resolver",
+            "/usr/local/lib/postfix-mta-sts-resolver/bin/pip install postfix-mta-sts-resolver",
+        ],
+    )
+
+    systemd_unit = files.put(
+        name="upload mta-sts-daemon systemd unit",
+        src=importlib.resources.files(__package__).joinpath(
+            "postfix/mta-sts-daemon.service"
+        ),
+        dest="/etc/systemd/system/mta-sts-daemon.service",
+        user="root",
+        group="root",
+        mode="644",
+    )
+    need_restart |= systemd_unit.changed
+
+    return need_restart
+
+
 def _configure_postfix(domain: str, debug: bool = False) -> bool:
     """Configures Postfix SMTP server."""
     need_restart = False
@@ -221,6 +270,16 @@ def _configure_nginx(domain: str, debug: bool = False) -> bool:
     )
     need_restart |= autoconfig.changed
 
+    mta_sts_config = files.template(
+        src=importlib.resources.files(__package__).joinpath("nginx/mta-sts.txt.j2"),
+        dest="/var/www/html/.well-known/mta-sts.txt",
+        user="root",
+        group="root",
+        mode="644",
+        config={"domain_name": domain},
+    )
+    need_restart |= mta_sts_config.changed
+
     return need_restart
 
 
@@ -245,7 +304,7 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
     )
 
     # Deploy acmetool to have TLS certificates.
-    deploy_acmetool(nginx_hook=True, domains=[mail_server])
+    deploy_acmetool(nginx_hook=True, domains=[mail_server, f"mta-sts.{mail_server}"])
 
     apt.packages(
         name="Install Postfix",
@@ -276,6 +335,7 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
     postfix_need_restart = _configure_postfix(mail_domain, debug=debug)
     opendkim_need_restart = _configure_opendkim(mail_domain, dkim_selector)
     nginx_need_restart = _configure_nginx(mail_domain)
+    mta_sts_need_restart = _install_mta_sts_daemon()
 
     # deploy web pages and info if we have them
     pkg_root = importlib.resources.files(__package__)
@@ -291,6 +351,15 @@ def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> N
         restarted=opendkim_need_restart,
     )
 
+    systemd.service(
+        name="Start and enable MTA-STS daemon",
+        service="mta-sts-daemon.service",
+        daemon_reload=True,
+        running=True,
+        enabled=True,
+        restarted=mta_sts_need_restart,
+    )
+
     systemd.service(
         name="Start and enable Postfix",
         service="postfix.service",

deploy-chatmail/src/deploy_chatmail/acmetool/__init__.py

@@ -46,8 +46,7 @@ def deploy_acmetool(nginx_hook=False, email="", domains=[]):
         mode="644",
     )
 
-    for domain in domains:
+    server.shell(
-        server.shell(
+        name=f"Request certificate for: { ', '.join(domains) }",
-            name=f"Request certificate for {domain}",
+        commands=[f"acmetool want { ' '.join(domains)}"],
-            commands=[f"acmetool want {domain}"],
+    )
-        )

deploy-chatmail/src/deploy_chatmail/dovecot/dovecot.conf.j2

@@ -19,7 +19,7 @@ mail_plugins = quota
 # these are the capabilities Delta Chat cares about actually 
 # so let's keep the network overhead per login small
 # https://github.com/deltachat/deltachat-core-rust/blob/master/src/imap/capabilities.rs
-imap_capability = IMAP4rev1 IDLE MOVE QUOTA CONDSTORE
+imap_capability = IMAP4rev1 IDLE MOVE QUOTA CONDSTORE NOTIFY
 
 
 # Authentication for system users.

deploy-chatmail/src/deploy_chatmail/nginx/mta-sts.txt.j2

@@ -0,0 +1,4 @@
+version: STSv1
+mode: enforce
+mx: {{ config.domain_name }}
+max_age: 2419200

deploy-chatmail/src/deploy_chatmail/nginx/nginx.conf.j2

@@ -42,6 +42,10 @@ http {
 			# as directory, then fall back to displaying a 404.
 			try_files $uri $uri/ =404;
 		}
+
+        location /new_email {
+            proxy_pass http://localhost:3691/;
+        }
 	}
 }
 

deploy-chatmail/src/deploy_chatmail/opendkim/opendkim.conf

@@ -20,7 +20,7 @@ Domain			{{ config.domain_name }}
 Selector		{{ config.opendkim_selector }}
 KeyFile		  /etc/dkimkeys/{{ config.opendkim_selector }}.private
 KeyTable          /etc/dkimkeys/KeyTable
-SigningTable      /etc/dkimkeys/SigningTable
+SigningTable      refile:/etc/dkimkeys/SigningTable
 
 # In Debian, opendkim runs as user "opendkim". A umask of 007 is required when
 # using a local socket with MTAs that access the socket as a non-privileged

deploy-chatmail/src/deploy_chatmail/postfix/main.cf.j2

@@ -23,6 +23,7 @@ smtpd_tls_security_level=may
 smtp_tls_CApath=/etc/ssl/certs
 smtp_tls_security_level=may
 smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
+smtp_tls_policy_maps = socketmap:inet:127.0.0.1:8461:postfix
 
 smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
 myhostname = {{ config.domain_name }}

deploy-chatmail/src/deploy_chatmail/postfix/master.cf.j2

@@ -32,6 +32,7 @@ submission inet n       -       y       -       -       smtpd
   -o smtpd_recipient_restrictions=
   -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
   -o milter_macro_daemon_name=ORIGINATING
+  -o smtpd_client_connection_count_limit=1000
   -o smtpd_proxy_filter=127.0.0.1:10080
 smtps     inet  n       -       y       -       -       smtpd
   -o syslog_name=postfix/smtps
@@ -46,6 +47,7 @@ smtps     inet  n       -       y       -       -       smtpd
   -o smtpd_sender_restrictions=$mua_sender_restrictions
   -o smtpd_recipient_restrictions=
   -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
+  -o smtpd_client_connection_count_limit=1000
   -o milter_macro_daemon_name=ORIGINATING
   -o smtpd_proxy_filter=127.0.0.1:10080
 #628       inet  n       -       y       -       -       qmqpd

deploy-chatmail/src/deploy_chatmail/postfix/mta-sts-daemon.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=Postfix MTA-STS resolver daemon
+
+[Service]
+ExecStart=/usr/local/lib/postfix-mta-sts-resolver/bin/mta-sts-daemon
+Restart=always
+RestartSec=30
+
+[Install]
+WantedBy=multi-user.target

deploy-chatmail/src/deploy_chatmail/postfix/mta-sts-daemon.yml

@@ -0,0 +1,13 @@
+host: 127.0.0.1
+port: 8461
+reuse_port: true
+shutdown_timeout: 20
+cache:
+  type: internal
+  options:
+    cache_size: 10000
+proactive_policy_fetching:
+  enabled: true
+default_zone:
+  strict_testing: false
+  timeout: 4

scripts/generate-dns-zone.sh

@@ -15,6 +15,9 @@ _submission._tcp.$CHATMAIL_DOMAIN.  SRV 0 1 587 $CHATMAIL_DOMAIN.
 _submissions._tcp.$CHATMAIL_DOMAIN. SRV 0 1 465 $CHATMAIL_DOMAIN.
 _imap._tcp.$CHATMAIL_DOMAIN.        SRV 0 1 143 $CHATMAIL_DOMAIN.
 _imaps._tcp.$CHATMAIL_DOMAIN.       SRV 0 1 993 $CHATMAIL_DOMAIN.
-$CHATMAIL_DOMAIN. IN CAA 0 issue "letsencrypt.org; accounturi=$ACME_ACCOUNT_URL"
+$CHATMAIL_DOMAIN. IN CAA 128 issue "letsencrypt.org;accounturi=$ACME_ACCOUNT_URL"
+_mta-sts.$CHATMAIL_DOMAIN. IN TXT "v=STSv1; id=$(date -u '+%Y%m%d%H%M')"
+mta-sts.$CHATMAIL_DOMAIN. IN CNAME $CHATMAIL_DOMAIN.
+_smtp._tls.$CHATMAIL_DOMAIN. IN TXT "v=TLSRPTv1;rua=mailto:$EMAIL"
 EOF
 $SSH opendkim-genzone -F | sed 's/^;.*$//;/^$/d'

tests/chatmaild/test_doveauth.py

@@ -1,12 +1,12 @@
 import json
-
+import sys
 import pytest
 import threading
 import queue
 import traceback
 
-import chatmaild.dictproxy
+import chatmaild.doveauth
-from chatmaild.dictproxy import get_user_data, lookup_passdb, handle_dovecot_request
+from chatmaild.doveauth import get_user_data, lookup_passdb, handle_dovecot_request
 from chatmaild.database import Database, DBError
 
 
@@ -30,7 +30,7 @@ def test_dont_overwrite_password_on_wrong_login(db):
 def test_nocreate_file(db, monkeypatch, tmpdir):
     p = tmpdir.join("nocreate")
     p.write("")
-    monkeypatch.setattr(chatmaild.dictproxy, "NOCREATE_FILE", str(p))
+    monkeypatch.setattr(chatmaild.doveauth, "NOCREATE_FILE", str(p))
     lookup_passdb(db, "newuser1@something.org", "zequ0Aimuchoodaechik")
     assert not get_user_data(db, "newuser1@something.org")
 
@@ -60,27 +60,31 @@ def test_handle_dovecot_request(db):
     assert userdata["password"].startswith("{SHA512-CRYPT}")
 
 
-def test_100_concurrent_lookups(db):
+def test_100_concurrent_lookups_different_accounts(db, gencreds):
-    num = 100
+    num_threads = 100
-    dbs = [Database(db.path) for i in range(num)]
+    req_per_thread = 5
-    print(f"created {num} databases")
     results = queue.Queue()
 
     def lookup(db):
-        try:
+        for i in range(req_per_thread):
-            lookup_passdb(db, "something@c1.testrun.org", "Pieg9aeToe3eghuthe5u")
+            addr, password = gencreds()
-        except Exception:
+            try:
-            results.put(traceback.format_exc())
+                lookup_passdb(db, addr, password)
-        else:
+            except Exception:
-            results.put(None)
+                results.put(traceback.format_exc())
+            else:
+                results.put(None)
 
-    threads = [threading.Thread(target=lookup, args=(db,), daemon=True) for db in dbs]
+    threads = []
+    for i in range(num_threads):
+        thread = threading.Thread(target=lookup, args=(db,), daemon=True)
+        threads.append(thread)
 
-    print(f"created {num} threads, starting them and waiting for results")
+    print(f"created {num_threads} threads, starting them and waiting for results")
     for thread in threads:
         thread.start()
 
-    for _ in dbs:
+    for i in range(num_threads * req_per_thread):
         res = results.get()
         if res is not None:
             pytest.fail(f"concurrent lookup failed\n{res}")

www/nine.testrun.org/index.html

@@ -20,15 +20,14 @@
             box-sizing: border-box;
             padding: 9px;
             font-size: 18px;
-            font-family: "Courier New", monospace;
+            font-family: "Swansea", "Helvetica", sans-serif;
-            color: white;
+            color: black;
-            background-position: left top;
+        }
-            background-image: url(collage-bg.png);
+        a {
-            background-repeat: no-repeat;
+            color: black;
-            background-size: 100% 100%;
         }
         h1, h2, h3 {
-            font-size: 16px;
+            font-size: 18px;
             font-weight: bold;
         }
     </style>
@@ -37,24 +36,39 @@
     <div class="wrapper">
         <img class="section" src="collage-top.png" />
         <div class="section text">
-            <h1>welcome  to nine.testrun.org</h1>
+            <h1>Dear Delta Chat users and newcomers,</h1>
             <p>
-                to get an account,
+                welcome to the first public "chat-mail instance",
-                invent a word with <i>exactly</i> nine characters
+                a small and lean e-mail provider for smooth chatting.
-                and append @nine.testrun.org to it.
+                Install Delta Chat or add an account:
-                eg. <b>hellofits@nine.testrun.org</b>
+            <ul>
+                <li>Tap "LOG INTO YOUR E-MAIL ACCOUNT".</li>
+                <li>Address: invent a word with <i>exactly</i> nine characters
+                and append @nine.testrun.org to it.</li>
+                <li>Password: invent at least 10 characters. The first login sets your password.</li>
+            </ul>
+                If the e-mail address is not yet taken, you'll get that account.
             </p>
             <p>
-                if the email address is not yet taken, you'll get that account.
+            <img class="section" src="collage-down.png" />
-                the first login sets your password.
+
-                that's it.
+            <h2>What's behind it, how does it operate?</h2>
-            </p>
+            <p>nine.testrun.org is run
-        </div>
+                by a small group of devs and sysadmins, reachable via root@.
-        <img class="section" src="collage-down.png" />
+                They want to keep this instance running at least until end 2024.
-        <div class="section text">
+                Current limits:
-            <h1>faq</h1>
+            <ul>
-            <p><i>why are other email providers 1000 times more complicated?</i></p>
+            <li>Un-encrypted mails can not leave the chat-mail instance.</li>
-            <p>because they want to for $reasons</p>
+            <li>Use <a href="https://delta.chat/en/help#howtoe2ee">
+                guaranteed end-to-end encryption via QR code scans</a>
+                to setup contact with users outside of the chat-mail instance.
+            </li>
+            <li>You may send up to 60 messages per minute.</li>
+            <li>Messages are unconditionally removed 40 days after arrival.</li>
+            <li>Max storage per user is 100MB.</li>
+            </ul>
+            <h2>Why are other email providers 1000 times more complicated?</h2>
+            <p>¯\_(ツ)_/¯</p>
         </div>
     </div>
 </body>