--- a/src/usr/local/www/vpn_openvpn_server.php
+++ b/src/usr/local/www/vpn_openvpn_server.php
@@ -246,7 +246,10 @@
 		}
 
 		$pconfig['nbdd_server1'] = $a_server[$id]['nbdd_server1'];
-		if ($pconfig['nbdd_server1']) {
+		$pconfig['nbdd_server2'] = $a_server[$id]['nbdd_server2'];
+
+		if ($pconfig['nbdd_server1'] ||
+			$pconfig['nbdd_server2']) {
 			$pconfig['nbdd_server_enable'] = true;
 		}
 
@@ -560,11 +563,15 @@
 				$input_errors[] = gettext("The field 'WINS Server #2' must contain a valid IP address");
 			}
 		}
+
 		if ($pconfig['nbdd_server_enable']) {
 			if (!empty($pconfig['nbdd_server1']) && !is_ipaddr(trim($pconfig['nbdd_server1']))) {
 				$input_errors[] = gettext("The field 'NetBIOS Data Distribution Server #1' must contain a valid IP address");
 			}
+			if (!empty($pconfig['nbdd_server2']) && !is_ipaddr(trim($pconfig['nbdd_server2']))) {
+				$input_errors[] = gettext("The field 'NetBIOS Data Distribution Server #2' must contain a valid IP address");
 			}
+		}
 
 		if (!empty($pconfig['netbios_ntype']) &&
 			!array_key_exists($pconfig['netbios_ntype'], $netbios_nodetypes)) {
@@ -819,24 +826,24 @@
 		}
 
 		$server['netbios_enable'] = $pconfig['netbios_enable'];
+		if ($pconfig['netbios_enable']) {
 		$server['netbios_ntype'] = $pconfig['netbios_ntype'];
 		$server['netbios_scope'] = $pconfig['netbios_scope'];
 
-		$server['create_gw'] = $pconfig['create_gw'];
-		$server['verbosity_level'] = $pconfig['verbosity_level'];
-
-		if ($pconfig['netbios_enable']) {
-
 			if ($pconfig['wins_server_enable']) {
 				$server['wins_server1'] = $pconfig['wins_server1'];
 				$server['wins_server2'] = $pconfig['wins_server2'];
 			}
 
-			if ($pconfig['dns_server_enable']) {
+			if ($pconfig['nbdd_server_enable']) {
 				$server['nbdd_server1'] = $pconfig['nbdd_server1'];
+				$server['nbdd_server2'] = $pconfig['nbdd_server2'];
 			}
 		}
 
+		$server['create_gw'] = $pconfig['create_gw'];
+		$server['verbosity_level'] = $pconfig['verbosity_level'];
+
 		if ($_POST['duplicate_cn'] == "yes") {
 			$server['duplicate_cn'] = true;
 		}
@@ -1682,25 +1689,58 @@
 
 	$section->addInput(new Form_Checkbox(
 		'wins_server_enable',
-		'WINS server enable',
+		'WINS servers',
 		'Provide a WINS server list to clients',
 		$pconfig['wins_server_enable']
 	));
 
-	$section->addInput(new Form_Input(
+	$group = new Form_Group(null);
+
+	$group->add(new Form_Input(
 		'wins_server1',
-		'WINS Server 1',
+		null,
 		'text',
 		$pconfig['wins_server1']
-	));
+	))->setHelp('Server 1');
 
-	$section->addInput(new Form_Input(
+	$group->add(new Form_Input(
 		'wins_server2',
-		'WINS Server 2',
+		null,
 		'text',
 		$pconfig['wins_server2']
+	))->setHelp('Server 2');
+
+	$group->addClass('winsservers');
+
+	$section->add($group);
+
+	$section->addInput(new Form_Checkbox(
+		'nbdd_server_enable',
+		'NBDD servers',
+		'Provide a NetBIOS over TCP/IP Datagram Distribution Servers list to clients',
+		$pconfig['nbdd_server_enable']
 	));
 
+	$group = new Form_Group(null);
+
+	$group->add(new Form_Input(
+		'nbdd_server1',
+		null,
+		'text',
+		$pconfig['nbdd_server1']
+	))->setHelp('Server 1');
+
+	$group->add(new Form_Input(
+		'nbdd_server2',
+		null,
+		'text',
+		$pconfig['nbdd_server2']
+	))->setHelp('Server 2');
+
+	$group->addClass('nbddservers');
+
+	$section->add($group);
+
 	$form->add($section);
 
 	$section = new Form_Section('Advanced Configuration');
@@ -2151,13 +2191,13 @@
 	}
 
 	function wins_server_change() {
-		var hide  = ! $('#wins_server_enable').prop('checked')
+		hideClass('winsservers', ! $('#wins_server_enable').prop('checked'));
+	}
 
-		hideInput('wins_server1', hide);
-		hideInput('wins_server2', hide);
+	function nbdd_server_change() {
+		hideClass('nbddservers', ! $('#nbdd_server_enable').prop('checked'));
 	}
 
-
 	function ntp_server_change() {
 		var hide  = ! $('#ntp_server_enable').prop('checked')
 
@@ -2166,13 +2206,22 @@
 	}
 
 	function netbios_change() {
-		var hide  = ! $('#netbios_enable').prop('checked')
-
-		hideInput('netbios_ntype', hide);
-		hideInput('netbios_scope', hide);
-		hideCheckbox('wins_server_enable', hide);
+		if ($('#netbios_enable').prop('checked')) {
+			hideInput('netbios_ntype', false);
+			hideInput('netbios_scope', false);
+			hideCheckbox('wins_server_enable', false);
 			wins_server_change();
+			hideCheckbox('nbdd_server_enable', false);
+			nbdd_server_change();
+		} else {
+			hideInput('netbios_ntype', true);
+			hideInput('netbios_scope', true);
+			hideCheckbox('wins_server_enable', true);
+			hideClass('winsservers', true);
+			hideCheckbox('nbdd_server_enable', true);
+			hideClass('nbddservers', true);
 		}
+	}
 
 	function tuntap_change() {
 
@@ -2302,6 +2351,11 @@
 		wins_server_change();
 	});
 
+	// NBDD server port
+	$('#nbdd_server_enable').click(function () {
+		nbdd_server_change();
+	});
+
 	// DNS server port
 	$('#dns_server_enable').click(function () {
 		dns_server_change();
@@ -2438,6 +2492,7 @@
 	dns_domain_change();
 	dns_server_change();
 	wins_server_change();
+	nbdd_server_change
 	ntp_server_change();
 	netbios_change();
 	tuntap_change();


--- a/src/usr/local/www/vpn_openvpn_csc.php
+++ b/src/usr/local/www/vpn_openvpn_csc.php
@@ -64,7 +64,7 @@
 		exit;
 	}
 
-	if (!$user_can_edit_advanced && !empty($a_csc[$id]['custom_options'])) {
+	if (!$user_can_edit_advanced && !empty_field($a_csc[$id]['custom_options'])) {
 		$input_errors[] = gettext("This user does not have sufficient privileges to delete an instance with Advanced options set.");
 	} else {
 		$wc_msg = sprintf(gettext('Deleted OpenVPN client specific override %1$s %2$s'), $a_csc[$id]['common_name'], $a_csc[$id]['description']);
@@ -96,7 +96,7 @@
 		$pconfig['remove_route'] = $a_csc[$id]['remove_route'];
 
 		$pconfig['dns_domain'] = $a_csc[$id]['dns_domain'];
-		if ($pconfig['dns_domain']) {
+		if (!empty_field($pconfig['dns_domain'])) {
 			$pconfig['dns_domain_enable'] = true;
 		}
 
@@ -105,18 +105,18 @@
 		$pconfig['dns_server3'] = $a_csc[$id]['dns_server3'];
 		$pconfig['dns_server4'] = $a_csc[$id]['dns_server4'];
 
-		if ($pconfig['dns_server1'] ||
-		    $pconfig['dns_server2'] ||
-		    $pconfig['dns_server3'] ||
-		    $pconfig['dns_server4']) {
+		if (!empty_field($pconfig['dns_server1']) ||
+				!empty_field($pconfig['dns_server2']) ||
+				!empty_field($pconfig['dns_server3']) ||
+				!empty_field($pconfig['dns_server4'])) {
 			$pconfig['dns_server_enable'] = true;
 		}
 
 		$pconfig['ntp_server1'] = $a_csc[$id]['ntp_server1'];
 		$pconfig['ntp_server2'] = $a_csc[$id]['ntp_server2'];
 
-		if ($pconfig['ntp_server1'] ||
-		    $pconfig['ntp_server2']) {
+		if (!empty_field($pconfig['ntp_server1']) ||
+				!empty_field($pconfig['ntp_server2'])) {
 			$pconfig['ntp_server_enable'] = true;
 		}
 
@@ -127,13 +127,16 @@
 		$pconfig['wins_server1'] = $a_csc[$id]['wins_server1'];
 		$pconfig['wins_server2'] = $a_csc[$id]['wins_server2'];
 
-		if ($pconfig['wins_server1'] ||
-		    $pconfig['wins_server2']) {
+		if (!empty_field($pconfig['wins_server1']) ||
+				!empty_field($pconfig['wins_server2'])) {
 			$pconfig['wins_server_enable'] = true;
 		}
 
 		$pconfig['nbdd_server1'] = $a_csc[$id]['nbdd_server1'];
-		if ($pconfig['nbdd_server1']) {
+		$pconfig['nbdd_server2'] = $a_csc[$id]['nbdd_server2'];
+
+		if (!empty_field($pconfig['nbdd_server1']) ||
+				!empty_field($pconfig['nbdd_server2'])) {
 			$pconfig['nbdd_server_enable'] = true;
 		}
 	}
@@ -155,7 +158,8 @@
 	    !$user_can_edit_advanced) {
 		$input_errors[] = gettext("This user does not have sufficient privileges to edit Advanced options on this instance.");
 	}
-	if (!$user_can_edit_advanced && !empty($a_csc[$id]['custom_options'])) {
+	if (!$user_can_edit_advanced && !empty_field($a_csc[$id]['custom_options'])) {
+		// restore custom options field to its original value
 		$pconfig['custom_options'] = $a_csc[$id]['custom_options'];
 	}
 
@@ -171,11 +175,11 @@
 		}
 	}
 
-	if (!empty($pconfig['tunnel_network']) && !openvpn_validate_tunnel_network($pconfig['tunnel_network'], 'ipv4')) {
+	if (!empty_field($pconfig['tunnel_network']) && !openvpn_validate_tunnel_network($pconfig['tunnel_network'], 'ipv4')) {
 		$input_errors[] = gettext("The field 'IPv4 Tunnel Network' must contain a valid IPv4 subnet with CIDR mask or an alias with a single IPv4 subnet with CIDR mask.");
 	}
 
-	if (!empty($pconfig['tunnel_networkv6']) && !openvpn_validate_tunnel_network($pconfig['tunnel_networkv6'], 'ipv6')) {
+	if (!empty_field($pconfig['tunnel_networkv6']) && !openvpn_validate_tunnel_network($pconfig['tunnel_networkv6'], 'ipv6')) {
 		$input_errors[] = gettext("The field 'IPv6 Tunnel Network' must contain a valid IPv6 prefix or an alias with a single IPv6 prefix.");
 	}
 
@@ -196,49 +200,53 @@
 	}
 
 	if ($pconfig['dns_server_enable']) {
-		if (!empty($pconfig['dns_server1']) && !is_ipaddr(trim($pconfig['dns_server1']))) {
+		if (!empty_field($pconfig['dns_server1']) && !is_ipaddr(trim($pconfig['dns_server1']))) {
 			$input_errors[] = gettext("The field 'DNS Server #1' must contain a valid IP address");
 		}
-		if (!empty($pconfig['dns_server2']) && !is_ipaddr(trim($pconfig['dns_server2']))) {
+		if (!empty_field($pconfig['dns_server2']) && !is_ipaddr(trim($pconfig['dns_server2']))) {
 			$input_errors[] = gettext("The field 'DNS Server #2' must contain a valid IP address");
 		}
-		if (!empty($pconfig['dns_server3']) && !is_ipaddr(trim($pconfig['dns_server3']))) {
+		if (!empty_field($pconfig['dns_server3']) && !is_ipaddr(trim($pconfig['dns_server3']))) {
 			$input_errors[] = gettext("The field 'DNS Server #3' must contain a valid IP address");
 		}
-		if (!empty($pconfig['dns_server4']) && !is_ipaddr(trim($pconfig['dns_server4']))) {
+		if (!empty_field($pconfig['dns_server4']) && !is_ipaddr(trim($pconfig['dns_server4']))) {
 			$input_errors[] = gettext("The field 'DNS Server #4' must contain a valid IP address");
 		}
 	}
 
 	if ($pconfig['ntp_server_enable']) {
-		if (!empty($pconfig['ntp_server1']) && !is_ipaddr(trim($pconfig['ntp_server1']))) {
+		if (!empty_field($pconfig['ntp_server1']) && !is_ipaddr(trim($pconfig['ntp_server1']))) {
 			$input_errors[] = gettext("The field 'NTP Server #1' must contain a valid IP address");
 		}
-		if (!empty($pconfig['ntp_server2']) && !is_ipaddr(trim($pconfig['ntp_server2']))) {
+		if (!empty_field($pconfig['ntp_server2']) && !is_ipaddr(trim($pconfig['ntp_server2']))) {
 			$input_errors[] = gettext("The field 'NTP Server #2' must contain a valid IP address");
 		}
-		if (!empty($pconfig['ntp_server3']) && !is_ipaddr(trim($pconfig['ntp_server3']))) {
+		if (!empty_field($pconfig['ntp_server3']) && !is_ipaddr(trim($pconfig['ntp_server3']))) {
 			$input_errors[] = gettext("The field 'NTP Server #3' must contain a valid IP address");
 		}
-		if (!empty($pconfig['ntp_server4']) && !is_ipaddr(trim($pconfig['ntp_server4']))) {
+		if (!empty_field($pconfig['ntp_server4']) && !is_ipaddr(trim($pconfig['ntp_server4']))) {
 			$input_errors[] = gettext("The field 'NTP Server #4' must contain a valid IP address");
 		}
 	}
 
 	if ($pconfig['netbios_enable']) {
 		if ($pconfig['wins_server_enable']) {
-			if (!empty($pconfig['wins_server1']) && !is_ipaddr(trim($pconfig['wins_server1']))) {
+			if (!empty_field($pconfig['wins_server1']) && !is_ipaddr(trim($pconfig['wins_server1']))) {
 				$input_errors[] = gettext("The field 'WINS Server #1' must contain a valid IP address");
 			}
-			if (!empty($pconfig['wins_server2']) && !is_ipaddr(trim($pconfig['wins_server2']))) {
+			if (!empty_field($pconfig['wins_server2']) && !is_ipaddr(trim($pconfig['wins_server2']))) {
 				$input_errors[] = gettext("The field 'WINS Server #2' must contain a valid IP address");
 			}
 		}
+
 		if ($pconfig['nbdd_server_enable']) {
-			if (!empty($pconfig['nbdd_server1']) && !is_ipaddr(trim($pconfig['nbdd_server1']))) {
+			if (!empty_field($pconfig['nbdd_server1']) && !is_ipaddr(trim($pconfig['nbdd_server1']))) {
 				$input_errors[] = gettext("The field 'NetBIOS Data Distribution Server #1' must contain a valid IP address");
 			}
+			if (!empty_field($pconfig['nbdd_server2']) && !is_ipaddr(trim($pconfig['nbdd_server2']))) {
+				$input_errors[] = gettext("The field 'NetBIOS Data Distribution Server #2' must contain a valid IP address");
 			}
+		}
 
 		if (!empty($pconfig['netbios_ntype']) &&
 			!array_key_exists($pconfig['netbios_ntype'], $netbios_nodetypes)) {
@@ -294,17 +302,19 @@
 		}
 
 		$csc['netbios_enable'] = $pconfig['netbios_enable'];
+
+		if ($pconfig['netbios_enable']) {
 		$csc['netbios_ntype'] = $pconfig['netbios_ntype'];
 		$csc['netbios_scope'] = $pconfig['netbios_scope'];
 
-		if ($pconfig['netbios_enable']) {
 			if ($pconfig['wins_server_enable']) {
 				$csc['wins_server1'] = $pconfig['wins_server1'];
 				$csc['wins_server2'] = $pconfig['wins_server2'];
 			}
 
-			if ($pconfig['dns_server_enable']) {
+			if ($pconfig['nbdd_server_enable']) {
 				$csc['nbdd_server1'] = $pconfig['nbdd_server1'];
+				$csc['nbdd_server2'] = $pconfig['nbdd_server2'];
 			}
 		}
 
@@ -323,7 +333,7 @@
 			$wc_msg = sprintf(gettext('Added OpenVPN client specific override %1$s %2$s'), $csc['common_name'], $csc['description']);
 		}
 
-		if (!empty($old_csc['common_name'])) {
+		if (!empty_field($old_csc['common_name'])) {
 			openvpn_delete_csc($old_csc);
 		}
 		openvpn_resync_csc($csc);
@@ -499,7 +509,7 @@
 		'DNS Default Domain',
 		'Provide a default domain name to clients',
 		$pconfig['dns_domain_enable']
-	))->toggles('.dnsdomain');
+	));
 
 	$group = new Form_Group('DNS Domain');
 	$group->addClass('dnsdomain');
@@ -519,7 +529,7 @@
 		'DNS Servers',
 		'Provide a DNS server list to clients',
 		$pconfig['dns_server_enable']
-	))->toggles('.dnsservers');
+	));
 
 	$group = new Form_Group(null);
 	$group->addClass('dnsservers');
@@ -560,7 +570,7 @@
 		'NTP Servers',
 		'Provide an NTP server list to clients',
 		$pconfig['ntp_server_enable']
-	))->toggles('.ntpservers');
+	));
 
 	$group = new Form_Group(null);
 	$group->addClass('ntpservers');
@@ -581,7 +591,7 @@
 
 	$section->add($group);
 
-	// NTP servers - For this section we need to use Javascript hiding since there
+	// Netbios - For this section we need to use Javascript hiding since there
 	// are nested toggles
 	$section->addInput(new Form_Checkbox(
 		'netbios_enable',
@@ -633,6 +643,33 @@
 
 	$section->add($group);
 
+	$section->addInput(new Form_Checkbox(
+		'nbdd_server_enable',
+		'NBDD servers',
+		'Provide a NetBIOS over TCP/IP Datagram Distribution Servers list to clients',
+		$pconfig['nbdd_server_enable']
+	));
+
+	$group = new Form_Group(null);
+
+	$group->add(new Form_Input(
+		'nbdd_server1',
+		null,
+		'text',
+		$pconfig['nbdd_server1']
+	))->setHelp('Server 1');
+
+	$group->add(new Form_Input(
+		'nbdd_server2',
+		null,
+		'text',
+		$pconfig['nbdd_server2']
+	))->setHelp('Server 2');
+
+	$group->addClass('nbddservers');
+
+	$section->add($group);
+
 	$custops = new Form_Textarea(
 		'custom_options',
 		'Advanced',
@@ -670,19 +707,46 @@
 <script type="text/javascript">
 //<![CDATA[
 events.push(function() {
+	function dnsdomain_change() {
+		if ($('#dns_domain_enable').prop('checked')) {
+			hideClass('dnsdomain', false);
+		} else {
+			hideClass('dnsdomain', true);
+		}
+	}
 
-	// Hide/show that section, but have to also respect the wins_server_enable checkbox
+	function dnsservers_change() {
+		if ($('#dns_server_enable').prop('checked')) {
+			hideClass('dnsservers', false);
+		} else {
+			hideClass('dnsservers', true);
+		}
+	}
+
+	function ntpservers_change() {
+		if ($('#ntp_server_enable').prop('checked')) {
+			hideClass('ntpservers', false);
+		} else {
+			hideClass('ntpservers', true);
+		}
+	}
+
+	// Hide/show that section, but have to also respect the wins_server_enable and nbdd_server_enable checkboxes
 	function setNetbios() {
 		if ($('#netbios_enable').prop('checked')) {
 			hideInput('netbios_ntype', false);
 			hideInput('netbios_scope', false);
 			hideCheckbox('wins_server_enable', false);
 			setWins();
+			hideCheckbox('nbdd_server_enable', false);
+			setNbdds();
 		} else {
 			hideInput('netbios_ntype', true);
 			hideInput('netbios_scope', true);
 			hideCheckbox('wins_server_enable', true);
 			hideClass('winsservers', true);
+			hideCheckbox('nbdd_server_enable', true);
+			hideClass('nbddservers', true);
 		}
 	}
 
@@ -690,8 +754,27 @@
 		hideClass('winsservers', ! $('#wins_server_enable').prop('checked'));
 	}
 
+	function setNbdds() {
+		hideClass('nbddservers', ! $('#nbdd_server_enable').prop('checked'));
+	}
+
 	// ---------- Click checkbox handlers ---------------------------------------------------------
 
+	 // On clicking DNS Default Domain
+	$('#dns_domain_enable').click(function () {
+		dnsdomain_change();
+	});
+
+	 // On clicking DNS Servers
+	$('#dns_server_enable').click(function () {
+		dnsservers_change();
+	});
+
+	 // On clicking NTP Servers
+	$('#ntp_server_enable').click(function () {
+		ntpservers_change();
+	});
+
 	// On clicking the netbios_enable checkbox
 	$('#netbios_enable').click(function () {
 		setNetbios();
@@ -702,9 +785,18 @@
 		setWins();
 	});
 
+	// On clicking the nbdd_server_enable checkbox
+	$('#nbdd_server_enable').click(function () {
+		setNbdds();
+	});
+
 	// ---------- On initial page load ------------------------------------------------------------
 
 	setNetbios();
+	dnsdomain_change();
+	dnsservers_change();
+	ntpservers_change();
+
 });
 //]]>
 </script>


--- a/src/etc/inc/openvpn.inc
+++ b/src/etc/inc/openvpn.inc
@@ -197,6 +197,12 @@
 	$openvpn_exit_notify_client[$i] = sprintf(gettext("Retry %dx"), $i);
 }
 
+// check if submitted form field is not empty
+function empty_field($str) {
+	$has_text = !is_bool($str) && strlen($str) > 0;
+	return !$has_text;
+}
+
 function openvpn_build_mode_list() {
 	global $openvpn_server_modes;
 
@@ -772,11 +778,11 @@
 
 	if ($settings['netbios_enable']) {
 
-		if (!empty($settings['dhcp_nbttype']) && ($settings['dhcp_nbttype'] != 0)) {
-			$conf .= "push \"dhcp-option NBT {$settings['dhcp_nbttype']}\"\n";
+		if (!empty($settings['netbios_ntype']) && ($settings['netbios_ntype'] != 0)) {
+			$conf .= "push \"dhcp-option NBT {$settings['netbios_ntype']}\"\n";
 		}
-		if (!empty($settings['dhcp_nbtscope'])) {
-			$conf .= "push \"dhcp-option NBS {$settings['dhcp_nbtscope']}\"\n";
+		if (!empty($settings['netbios_scope'])) {
+			$conf .= "push \"dhcp-option NBS {$settings['netbios_scope']}\"\n";
 		}
 
 		if (!empty($settings['wins_server1'])) {
@@ -788,6 +794,9 @@
 
 		if (!empty($settings['nbdd_server1'])) {
 			$conf .= "push \"dhcp-option NBDD {$settings['nbdd_server1']}\"\n";
+		}
+		if (!empty($settings['nbdd_server2'])) {
+			$conf .= "push \"dhcp-option NBDD {$settings['nbdd_server2']}\"\n";
 		}
 	}