Replace internal domain names with generic placeholders

MainWindow.axaml

@@ -18,7 +18,7 @@
       <Grid ColumnDefinitions="*,90,130,210" RowDefinitions="Auto,Auto,Auto,Auto" ColumnSpacing="10" RowSpacing="8">
         <StackPanel Grid.Row="0" Grid.Column="0">
           <TextBlock Text="Domain controller / LDAP host" />
-          <TextBox x:Name="LdapHostBox" PlaceholderText="NODC04.knno.local" />
+          <TextBox x:Name="LdapHostBox" PlaceholderText="dc01.contoso.local" />
         </StackPanel>
 
         <StackPanel Grid.Row="0" Grid.Column="1">
@@ -31,12 +31,12 @@
 
         <StackPanel Grid.Row="1" Grid.Column="0">
           <TextBlock Text="Search base DN" />
-          <TextBox x:Name="SearchBaseBox" PlaceholderText="DC=knno,DC=local" />
+          <TextBox x:Name="SearchBaseBox" PlaceholderText="DC=contoso,DC=local" />
         </StackPanel>
 
         <StackPanel Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2">
           <TextBlock Text="Bind username" />
-          <TextBox x:Name="BindUserBox" PlaceholderText="KNNO\adminuser or adminuser@knno.local" />
+          <TextBox x:Name="BindUserBox" PlaceholderText="CONTOSO\adminuser or adminuser@contoso.local" />
         </StackPanel>
 
         <StackPanel Grid.Row="1" Grid.Column="3">

MainWindow.axaml.cs

@@ -24,7 +24,7 @@ public partial class MainWindow : Window
         ActionBox.SelectedIndex = 0;
 
         LdapPortBox.Text = "636";
-        SearchBaseBox.Text = "DC=knno,DC=local";
+        SearchBaseBox.Text = "DC=contoso,DC=local";
         UseLdapsBox.IsChecked = true;
 
         RefreshConnectionHelp();
@@ -121,7 +121,7 @@ public partial class MainWindow : Window
             var host = LdapHostBox.Text?.Trim() ?? string.Empty;
             if (string.IsNullOrWhiteSpace(host))
             {
-                SetStatus("LDAP host is required, for example NODC04.knno.local.");
+                SetStatus("LDAP host is required, for example dc01.contoso.local.");
                 return;
             }
 
@@ -289,7 +289,7 @@ public partial class MainWindow : Window
         catch (Exception ex)
         {
             output.Add($"FAIL: DNS lookup failed for {host}: {FormatExceptionMessage(ex)}");
-            output.Add("Hint: check DNS suffix, VPN/internal network, or try the full DC FQDN such as nodc04.knno.local.");
+            output.Add("Hint: check DNS suffix, VPN/internal network, or try the full DC FQDN such as dc01.contoso.local.");
         }
 
         var tcp389 = await AdService.TestTcpPortAsync(host, 389, TimeSpan.FromSeconds(5));
@@ -339,7 +339,7 @@ public partial class MainWindow : Window
 
             if (!ldaps636.Success && !ignoreCertificateErrors)
             {
-                output.Add("Hint: if TCP 636 works but LDAPS bind fails on Linux, the Linux machine may not trust your internal CA chain. For testing only, try 'Ignore cert errors'. For production, install the KNNO root/intermediate CA into Linux trust.");
+                output.Add("Hint: if TCP 636 works but LDAPS bind fails on Linux, the Linux machine may not trust your internal CA chain. For testing only, try 'Ignore cert errors'. For production, install the your internal root/intermediate CA into Linux trust.");
             }
         }
         else
@@ -550,7 +550,7 @@ public partial class MainWindow : Window
 
         if (string.IsNullOrWhiteSpace(host))
         {
-            throw new InvalidOperationException("LDAP host is required, for example NODC04.knno.local.");
+            throw new InvalidOperationException("LDAP host is required, for example dc01.contoso.local.");
         }
 
         if (!int.TryParse(portText, NumberStyles.Integer, CultureInfo.InvariantCulture, out var port))
@@ -560,7 +560,7 @@ public partial class MainWindow : Window
 
         if (string.IsNullOrWhiteSpace(searchBase))
         {
-            throw new InvalidOperationException("Search base DN is required, for example DC=knno,DC=local.");
+            throw new InvalidOperationException("Search base DN is required, for example DC=contoso,DC=local.");
         }
 
         if (string.IsNullOrWhiteSpace(bindUser))