diff --git a/nsupdate/main/migrations/0011_auto_20170526_2113.py b/nsupdate/main/migrations/0011_auto_20170526_2113.py
new file mode 100644
index 0000000..f7721bd
--- /dev/null
+++ b/nsupdate/main/migrations/0011_auto_20170526_2113.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import django.core.validators
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0010_auto_20151229_1717'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='domain',
+            name='name',
+            field=models.CharField(help_text='Name of the zone where dynamic hosts may get added', unique=True, max_length=255, verbose_name='name', validators=[django.core.validators.RegexValidator(regex=b'([a-zA-Z0-9-_]+\\.)+[a-zA-Z0-9-_]{2,}', message='Invalid domain name')]),
+        ),
+    ]
diff --git a/nsupdate/main/models.py b/nsupdate/main/models.py
index 1a3fcef..57930c7 100644
--- a/nsupdate/main/models.py
+++ b/nsupdate/main/models.py
@@ -85,6 +85,7 @@ class Domain(models.Model):
     name = models.CharField(
         _("name"),
         max_length=255,  # RFC 2181 (and also: max length of unique fields)
+        validators=[RegexValidator(regex=r"([a-zA-Z0-9-_]+\.)+[a-zA-Z0-9-_]{2,}", message=_("Invalid domain name"))],
         unique=True,
         help_text=_("Name of the zone where dynamic hosts may get added"))
     nameserver_ip = models.GenericIPAddressField(
diff --git a/nsupdate/main/templates/main/domain_add.html b/nsupdate/main/templates/main/domain_add.html
index e417afe..e870926 100644
--- a/nsupdate/main/templates/main/domain_add.html
+++ b/nsupdate/main/templates/main/domain_add.html
@@ -2,6 +2,11 @@
 {% load i18n %}{% load bootstrap %}
 
 {% block content %}
+    <div class="alert alert-warning" role="alert">
+        <i class="fa fa-exclamation-triangle"
+           aria-hidden="true"></i> {% trans "This feature is for advanced users only! To use this feature, you need control over at least one nameserver which is able to accept dynamic updates (RFC 2136)." %}
+        <i class="fa fa-exclamation-triangle" aria-hidden="true"></i>
+    </div>
     <div class="row">
         <div class="col-md-6">
             <div class="well well-sm">
@@ -17,19 +22,22 @@
             <div class="well well-sm">
                 <h3>{% trans "Help" %}</h3>
                 <p>
-                   {% blocktrans trimmed %}
-                   Here you can add new domains (zones) which you control (and this is only useful if you
-                   have some own zone which you can update automatically).
-                   {% endblocktrans %}
+                    {% blocktrans trimmed %}
+                        Here you can add new domains (zones) which you control (and this is only
+                        useful if you
+                        have some own zone which you can update automatically).
+                    {% endblocktrans %}
                 </p>
                 <p>
-                   {% blocktrans trimmed %}
-                   You need to be able to configure the primary master nameserver of the zone so it accepts
-                   dynamic updates (via RFC 2136 "dynamic update" protocol) if the correct update secret is presented.
-                   {% endblocktrans %}
+                    {% blocktrans trimmed %}
+                        You need to be able to configure the primary master nameserver of the zone
+                        so it accepts
+                        dynamic updates (via RFC 2136 "dynamic update" protocol) if the correct
+                        update secret is presented.
+                    {% endblocktrans %}
                 </p>
                 <p>
-                   {% trans "We'll show you configuration examples after you add a domain." %}
+                    {% trans "We'll show you configuration examples after you add a domain." %}
                 </p>
             </div>
         </div>
diff --git a/nsupdate/main/templates/main/overview.html b/nsupdate/main/templates/main/overview.html
index c3bfc68..3c1ef2b 100644
--- a/nsupdate/main/templates/main/overview.html
+++ b/nsupdate/main/templates/main/overview.html
@@ -85,7 +85,7 @@
         <div class="col-md-12">
             <h3>
                 {% trans "Domains (yours first, then public)" %}
-                <a href="{% url 'add_domain' %}" class="btn btn-primary btn-sm">{% trans "Add Domain" %}</a>
+                <a href="{% url 'add_domain' %}" class="btn btn-default btn-sm">{% trans "Add Domain" %}</a>
             </h3>
             <table class="table">
             <thead>