email: Show DNS entries for all domains instead of just primary

- Promote reverse DNS information to primary heading.

- Add information that only one domain have reverse DNS configured.

- Clarify that ISP are also responsible for reverse DNS.

- Show reverse DNS records only for primary domain.

Tests:

- View email app. List of domains is shown in the domain section. Primary domain
is marked with a special icon.

- Clicking on the domain works. DNS and reverse DNS information is shown. DKIM
key information is present.

Signed-off-by: Sunil Mohan Adapa <sunil@medhas.org>
Reviewed-by: Benedek Nagy <contact@nbenedek.me>

plinth/modules/email/dns.py

@@ -46,9 +46,8 @@ class Entry:  # pylint: disable=too-many-instance-attributes
         return ' '.join(pieces)
 
 
-def get_entries():
-    """Return the list of DNS entries to make."""
-    domain = privileged.domain.get_domains()['primary_domain']
+def get_entries(domain: str) -> list[Entry]:
+    """Return the list of DNS entries to be set in DNS server for domain."""
     mx_spam_entries = [
         Entry(type_='MX', value=f'{domain}.'),
         Entry(type_='TXT', value='v=spf1 mx a ~all'),
@@ -77,10 +76,9 @@ def get_entries():
     return mx_spam_entries + dkim_entries + autoconfig_entries
 
 
-def get_reverse_entries() -> list[Entry]:
+def get_reverse_entries(domain: str) -> list[Entry]:
     """Return the list of reverse DNS entries to make."""
     entries = []
-    domain = privileged.domain.get_domains()['primary_domain']
     for ip_type in typing.get_args(typing.Literal['ipv4', 'ipv6']):
         try:
             ip_address = lookup_public_address(ip_type)

plinth/modules/email/templates/email-dns.html

@@ -0,0 +1,95 @@
+{% extends "base.html" %}
+{% comment %}
+# SPDX-License-Identifier: AGPL-3.0-or-later
+{% endcomment %}
+
+{% load i18n %}
+
+{% block content %}
+  <h3>{% trans "DNS Records for domain:" %} {{ domain }}</h3>
+
+  <p>
+    {% blocktrans trimmed %}
+      The following DNS records must be added manually on this domain for the
+      mail server to work properly for this domain.
+    {% endblocktrans %}
+  </p>
+
+  <div class="table-responsive">
+    <table class="table table-sm">
+      <thead>
+        <tr>
+          <th>{% trans "Domain" %}</th>
+          <th>{% trans "TTL" %}</th>
+          <th>{% trans "Class" %}</th>
+          <th>{% trans "Type" %}</th>
+          <th>{% trans "Priority" %}</th>
+          <th>{% trans "Weight" %}</th>
+          <th>{% trans "Port" %}</th>
+          <th>{% trans "Host/Target/Value" %}</th>
+        </tr>
+      </thead>
+      <tbody>
+        {% for dns_entry in dns_entries %}
+          <tr>
+            <td>{{ dns_entry.domain|default_if_none:"" }}</td>
+            <td>{{ dns_entry.ttl }}</td>
+            <td>{{ dns_entry.class_ }}</td>
+            <td>{{ dns_entry.type_ }}</td>
+            <td>{{ dns_entry.priority }}</td>
+            <td>{{ dns_entry.weight|default_if_none:"" }}</td>
+            <td>{{ dns_entry.port|default_if_none:"" }}</td>
+            <td class="text-break">{{ dns_entry.get_split_value }}</td>
+          </tr>
+        {% endfor %}
+      </tbody>
+    </table>
+  </div>
+
+  {% if domain == primary_domain %}
+    <h3>{% trans "Reverse DNS Records for IP Addresses" %}</h3>
+
+    <p>
+      {% blocktrans trimmed %}
+        If your {{ box_name }} runs on a cloud service infrastructure, you
+        should configure <a href="https://en.wikipedia.org/wiki/Reverse_DNS_lookup">
+        Reverse DNS lookup</a>. This isn't mandatory, however, it greatly improves
+        email deliverability. Reverse DNS isn't configured where your regular DNS
+        is. You should look for it in the settings of your VPS/ISP. Some providers
+        preconfigure the IP address part for you and you only have to set the
+        domain part. Only one of your domains can have Revese DNS lookup
+        configured unless you have multiple public IP addresses.
+      {% endblocktrans %}
+    </p>
+
+    <p>
+      {% blocktrans trimmed %}
+        An external service is used to lookup public IP address to show in the
+        following section. This can be configured in the privacy app.
+      {% endblocktrans %}
+    </p>
+
+    <div class="table-responsive">
+      <table class="table table-sm">
+        <thead>
+          <tr>
+            <th>{% trans "Host" %}</th>
+            <th>{% trans "TTL" %}</th>
+            <th>{% trans "Type" %}</th>
+            <th>{% trans "Host/Target/Value" %}</th>
+          </tr>
+        </thead>
+        <tbody>
+          {% for dns_entry in reverse_dns_entries %}
+            <tr>
+              <td>{{ dns_entry.domain|default_if_none:"" }}</td>
+              <td>{{ dns_entry.ttl }}</td>
+              <td>{{ dns_entry.type_ }}</td>
+              <td class="text-break">{{ dns_entry.get_split_value }}</td>
+            </tr>
+            {% endfor %}
+        </tbody>
+      </table>
+    </div>
+  {% endif %}
+{% endblock %}

plinth/modules/email/templates/email.html

@@ -17,82 +17,28 @@
 {% endblock %}
 
 {% block extra_content %}
-  {{ block.super }}
-
-  <h3>{% trans "DNS Records" %}</h3>
+  <h3>{% trans "Domains" %}</h3>
 
   <p>
     {% blocktrans trimmed %}
-      The following DNS records must be added manually on your primary domain
-      for the mail server to work properly.
+      The following domains are configured. View details to see the list of DNS
+      entries to be made for the domain.
     {% endblocktrans %}
   </p>
 
-  <div class="table-responsive">
-    <table class="table table-sm">
-      <thead>
-        <tr>
-          <th>{% trans "Domain" %}</th>
-          <th>{% trans "TTL" %}</th>
-          <th>{% trans "Class" %}</th>
-          <th>{% trans "Type" %}</th>
-          <th>{% trans "Priority" %}</th>
-          <th>{% trans "Weight" %}</th>
-          <th>{% trans "Port" %}</th>
-          <th>{% trans "Host/Target/Value" %}</th>
-        </tr>
-      </thead>
-      <tbody>
-        {% for dns_entry in dns_entries %}
-          <tr>
-            <td>{{ dns_entry.domain|default_if_none:"" }}</td>
-            <td>{{ dns_entry.ttl }}</td>
-            <td>{{ dns_entry.class_ }}</td>
-            <td>{{ dns_entry.type_ }}</td>
-            <td>{{ dns_entry.priority }}</td>
-            <td>{{ dns_entry.weight|default_if_none:"" }}</td>
-            <td>{{ dns_entry.port|default_if_none:"" }}</td>
-            <td class="text-break">{{ dns_entry.get_split_value }}</td>
-          </tr>
+  <div class="row">
+    <div class="col-md-6">
+      <div class="list-group">
+        {% for domain in all_domains %}
+          <div class="list-group-item">
+            <a href="{% url 'email:dns' domain %}"
+               title="{% blocktrans %}View domain: {{ domain }}{% endblocktrans %}">
+              {{ domain }}</a>
+            {% if domain == primary_domain %}<div class="app-icon fa fa-tag"></div>{% endif %}
+          </div>
         {% endfor %}
-      </tbody>
-    </table>
-  </div>
-
-  <h4>{% trans "Reverse DNS" %}</h4>
-
-  <p>
-    {% blocktrans trimmed %}
-      If your {{ box_name }} runs on a cloud service infrastructure, you
-      should configure <a href="https://en.wikipedia.org/wiki/Reverse_DNS_lookup">
-      Reverse DNS lookup</a>. This isn't mandatory, however, it greatly improves
-      email deliverability. Reverse DNS isn't configured where your regular DNS
-      is. You should look for it in the settings of your VPS. Some providers
-      preconfigure the IP address part for you and you only have to set the domain part.
-    {% endblocktrans %}
-  </p>
-
-  <div class="table-responsive">
-    <table class="table table-sm">
-      <thead>
-        <tr>
-          <th>{% trans "Host" %}</th>
-          <th>{% trans "TTL" %}</th>
-          <th>{% trans "Type" %}</th>
-          <th>{% trans "Host/Target/Value" %}</th>
-        </tr>
-      </thead>
-      <tbody>
-        {% for dns_entry in reverse_dns_entries %}
-          <tr>
-            <td>{{ dns_entry.domain|default_if_none:"" }}</td>
-            <td>{{ dns_entry.ttl }}</td>
-            <td>{{ dns_entry.type_ }}</td>
-            <td class="text-break">{{ dns_entry.get_split_value }}</td>
-          </tr>
-        {% endfor %}
-      </tbody>
-    </table>
+      </div>
+    </div>
   </div>
 
 {% endblock %}

plinth/modules/email/urls.py

@@ -3,7 +3,7 @@
 URLs for the email module.
 """
 
-from django.urls import path
+from django.urls import path, re_path
 from stronghold.decorators import public
 
 from plinth.utils import non_admin_view
@@ -12,6 +12,8 @@ from . import views
 
 urlpatterns = [
     path('apps/email/', views.EmailAppView.as_view(), name='index'),
+    re_path('apps/email/dns/(?P<domain>[^/]+)/$', views.DnsView.as_view(),
+            name='dns'),
     path('apps/email/aliases/', non_admin_view(views.AliasView.as_view()),
          name='aliases'),
     path('apps/email/config.xml', public(views.XmlView.as_view())),

plinth/modules/email/views.py

@@ -25,8 +25,7 @@ class EmailAppView(AppView):
     def get_context_data(self, **kwargs):
         """Add additional context data for rendering the template."""
         context = super().get_context_data(**kwargs)
-        context['dns_entries'] = dns.get_entries()
-        context['reverse_dns_entries'] = dns.get_reverse_entries()
+        context.update(privileged.domain.get_domains())
         return context
 
     def get_initial(self):
@@ -51,6 +50,21 @@ class EmailAppView(AppView):
         return super().form_valid(form)
 
 
+class DnsView(TemplateView):
+    """Show the DNS records to configure on a given domain."""
+    template_name = 'email-dns.html'
+
+    def get_context_data(self, **kwargs):
+        """Add additional context data for rendering the template."""
+        domain = self.kwargs['domain']
+        context = super().get_context_data(**kwargs)
+        primary_domain = privileged.domain.get_domains()['primary_domain']
+        context['primary_domain'] = primary_domain
+        context['dns_entries'] = dns.get_entries(domain)
+        context['reverse_dns_entries'] = dns.get_reverse_entries(domain)
+        return context
+
+
 class AliasView(FormView):
     """View to create, list, enable, disable and delete aliases.