diff --git a/core/admin/mailu/configuration.py b/core/admin/mailu/configuration.py
index 18b50061..b60b8a3e 100644
--- a/core/admin/mailu/configuration.py
+++ b/core/admin/mailu/configuration.py
@@ -54,6 +54,7 @@ DEFAULT_CONFIG = {
     'DKIM_PATH': '/dkim/{domain}.{selector}.key',
     'DEFAULT_QUOTA': 1000000000,
     'MESSAGE_RATELIMIT': '200/day',
+    'MESSAGE_RATELIMIT_EXEMPTION': '',
     'RECIPIENT_DELIMITER': '',
     # Web settings
     'SITENAME': 'Mailu',
@@ -154,6 +155,7 @@ class ConfigManager:
         self.config['PERMANENT_SESSION_LIFETIME'] = timedelta(hours=int(self.config['SESSION_LIFETIME']))
         hostnames = [host.strip() for host in self.config['HOSTNAMES'].split(',')]
         self.config['AUTH_RATELIMIT_EXEMPTION'] = set(ipaddress.ip_network(cidr, False) for cidr in (cidr.strip() for cidr in self.config['AUTH_RATELIMIT_EXEMPTION'].split(',')) if cidr)
+        self.config['MESSAGE_RATELIMIT_EXEMPTION'] = set([s for s in self.config['MESSAGE_RATELIMIT_EXEMPTION'].lower().replace(' ', '').split(',') if s])
         self.config['HOSTNAMES'] = ','.join(hostnames)
         self.config['HOSTNAME'] = hostnames[0]
 
diff --git a/core/admin/mailu/internal/views/postfix.py b/core/admin/mailu/internal/views/postfix.py
index ab965967..ed951943 100644
--- a/core/admin/mailu/internal/views/postfix.py
+++ b/core/admin/mailu/internal/views/postfix.py
@@ -149,6 +149,8 @@ def postfix_sender_login(sender):
 def postfix_sender_rate(sender):
     """ Rate limit outbound emails per sender login
     """
+    if sender in flask.current_app.config['MESSAGE_RATELIMIT_EXEMPTION']:
+        flask.abort(404)
     user = models.User.get(sender) or flask.abort(404)
     return flask.abort(404) if user.sender_limiter.hit() else flask.jsonify("450 4.2.1 You are sending too many emails too fast.")
 
diff --git a/core/admin/mailu/internal/views/rspamd.py b/core/admin/mailu/internal/views/rspamd.py
index 8551eb8f..458dbb81 100644
--- a/core/admin/mailu/internal/views/rspamd.py
+++ b/core/admin/mailu/internal/views/rspamd.py
@@ -14,17 +14,14 @@ def vault_error(*messages, status=404):
 
 @internal.route("/rspamd/vault/v1/dkim/<domain_name>", methods=['GET'])
 def rspamd_dkim_key(domain_name):
-    domain = models.Domain.query.get(domain_name) or flask.abort(vault_error('unknown domain'))
-    key = domain.dkim_key or flask.abort(vault_error('no dkim key', status=400))
-    return flask.jsonify({
-        'data': {
-            'selectors': [
+    selectors = []
+    if domain := models.Domain.query.get(domain_name):
+        if key := domain.dkim_key:
+            selectors.append(
                 {
                     'domain'  : domain.name,
                     'key'     : key.decode('utf8'),
                     'selector': flask.current_app.config.get('DKIM_SELECTOR', 'dkim'),
                 }
-            ]
-        }
-    })
-
+            )
+    return flask.jsonify({'data': {'selectors': selectors}})
diff --git a/core/admin/mailu/sso/views/base.py b/core/admin/mailu/sso/views/base.py
index e948aeb7..390d5bbf 100644
--- a/core/admin/mailu/sso/views/base.py
+++ b/core/admin/mailu/sso/views/base.py
@@ -39,7 +39,7 @@ def login():
             flask.session.regenerate()
             flask_login.login_user(user)
             response = flask.redirect(destination)
-            response.set_cookie('rate_limit', utils.limiter.device_cookie(username), max_age=31536000, path=flask.url_for('sso.login'))
+            response.set_cookie('rate_limit', utils.limiter.device_cookie(username), max_age=31536000, path=flask.url_for('sso.login'), secure=app.config['SESSION_COOKIE_SECURE'], httponly=True)
             flask.current_app.logger.info(f'Login succeeded for {username} from {client_ip}.')
             return response
         else:
diff --git a/core/postfix/conf/main.cf b/core/postfix/conf/main.cf
index 5fffc330..8ac646da 100644
--- a/core/postfix/conf/main.cf
+++ b/core/postfix/conf/main.cf
@@ -17,7 +17,7 @@ queue_directory = /queue
 message_size_limit = {{ MESSAGE_SIZE_LIMIT }}
 
 # Relayed networks
-mynetworks = 127.0.0.1/32 [::1]/128 {{ SUBNET }} {{ RELAYNETS.split(",") | join(' ') }}
+mynetworks = 127.0.0.1/32 [::1]/128 {{ SUBNET }}  {% if RELAYNETS %}{{ RELAYNETS.split(",") | join(' ') }}{% endif %}
 
 # Empty alias list to override the configuration variable and disable NIS
 alias_maps =
diff --git a/docs/configuration.rst b/docs/configuration.rst
index 03817988..ccf49058 100644
--- a/docs/configuration.rst
+++ b/docs/configuration.rst
@@ -69,9 +69,11 @@ The ``MESSAGE_SIZE_LIMIT`` is the maximum size of a single email. It should not
 be too low to avoid dropping legitimate emails and should not be too high to
 avoid filling the disks with large junk emails.
 
-The ``MESSAGE_RATELIMIT`` is the limit of messages a single user can send. This is
-meant to fight outbound spam in case of compromised or malicious account on the
-server.
+The ``MESSAGE_RATELIMIT`` (default: 200/day) is the maximum number of messages
+a single user can send. ``MESSAGE_RATELIMIT_EXEMPTION`` contains a comma delimited
+list of user email addresses that are exempted from any restriction.  Those
+settings are meant to reduce outbound spam in case of compromised or malicious
+account on the server.
 
 The ``RELAYNETS`` (default: unset) is a comma delimited list of network addresses
 for which mail is relayed for with no authentication required. This should be