diff --git a/usr/local/www/interfaces.php b/usr/local/www/interfaces.php
index 0d4535e609..b79da655b6 100644
--- a/usr/local/www/interfaces.php
+++ b/usr/local/www/interfaces.php
@@ -1067,40 +1067,68 @@ if ($_POST['apply']) {
 				if($_POST['dhcp6usev4iface'] == "yes")
 					$wancfg['dhcp6usev4iface'] = true;
 
-				$wancfg['adv_dhcp6_interface_statement_send_options'] = $_POST['adv_dhcp6_interface_statement_send_options'];
-				$wancfg['adv_dhcp6_interface_statement_request_options'] = $_POST['adv_dhcp6_interface_statement_request_options'];
-				$wancfg['adv_dhcp6_interface_statement_information_only_enable'] = $_POST['adv_dhcp6_interface_statement_information_only_enable'];
-				$wancfg['adv_dhcp6_interface_statement_script'] = $_POST['adv_dhcp6_interface_statement_script'];
+				if (!empty($_POST['adv_dhcp6_interface_statement_send_options']))
+					$wancfg['adv_dhcp6_interface_statement_send_options'] = $_POST['adv_dhcp6_interface_statement_send_options'];
+				if (!empty($_POST['adv_dhcp6_interface_statement_request_options']))
+					$wancfg['adv_dhcp6_interface_statement_request_options'] = $_POST['adv_dhcp6_interface_statement_request_options'];
+				if (isset($_POST['adv_dhcp6_interface_statement_information_only_enable']))
+					$wancfg['adv_dhcp6_interface_statement_information_only_enable'] = $_POST['adv_dhcp6_interface_statement_information_only_enable'];
+				if (!empty($_POST['adv_dhcp6_interface_statement_script']))
+					$wancfg['adv_dhcp6_interface_statement_script'] = $_POST['adv_dhcp6_interface_statement_script'];
 
-				$wancfg['adv_dhcp6_id_assoc_statement_address_enable'] = $_POST['adv_dhcp6_id_assoc_statement_address_enable'];
-				$wancfg['adv_dhcp6_id_assoc_statement_address'] = $_POST['adv_dhcp6_id_assoc_statement_address'];
-				$wancfg['adv_dhcp6_id_assoc_statement_address_id'] = $_POST['adv_dhcp6_id_assoc_statement_address_id'];
-				$wancfg['adv_dhcp6_id_assoc_statement_address_pltime'] = $_POST['adv_dhcp6_id_assoc_statement_address_pltime'];
-				$wancfg['adv_dhcp6_id_assoc_statement_address_vltime'] = $_POST['adv_dhcp6_id_assoc_statement_address_vltime'];
+				if (isset($_POST['adv_dhcp6_id_assoc_statement_address_enable']))
+					$wancfg['adv_dhcp6_id_assoc_statement_address_enable'] = $_POST['adv_dhcp6_id_assoc_statement_address_enable'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_address']))
+					$wancfg['adv_dhcp6_id_assoc_statement_address'] = $_POST['adv_dhcp6_id_assoc_statement_address'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_address_id']))
+					$wancfg['adv_dhcp6_id_assoc_statement_address_id'] = $_POST['adv_dhcp6_id_assoc_statement_address_id'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_address_pltime']))
+					$wancfg['adv_dhcp6_id_assoc_statement_address_pltime'] = $_POST['adv_dhcp6_id_assoc_statement_address_pltime'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_address_vltime']))
+					$wancfg['adv_dhcp6_id_assoc_statement_address_vltime'] = $_POST['adv_dhcp6_id_assoc_statement_address_vltime'];
 
-				$wancfg['adv_dhcp6_id_assoc_statement_prefix_enable'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_enable'];
-				$wancfg['adv_dhcp6_id_assoc_statement_prefix'] = $_POST['adv_dhcp6_id_assoc_statement_prefix'];
-				$wancfg['adv_dhcp6_id_assoc_statement_prefix_id'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_id'];
-				$wancfg['adv_dhcp6_id_assoc_statement_prefix_pltime'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_pltime'];
-				$wancfg['adv_dhcp6_id_assoc_statement_prefix_vltime'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_vltime'];
+				if (isset($_POST['adv_dhcp6_id_assoc_statement_prefix_enable']))
+					$wancfg['adv_dhcp6_id_assoc_statement_prefix_enable'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_enable'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_prefix']))
+					$wancfg['adv_dhcp6_id_assoc_statement_prefix'] = $_POST['adv_dhcp6_id_assoc_statement_prefix'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_prefix_id']))
+					$wancfg['adv_dhcp6_id_assoc_statement_prefix_id'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_id'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_prefix_pltime']))
+					$wancfg['adv_dhcp6_id_assoc_statement_prefix_pltime'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_pltime'];
+				if (!empty($_POST['adv_dhcp6_id_assoc_statement_prefix_vltime']))
+					$wancfg['adv_dhcp6_id_assoc_statement_prefix_vltime'] = $_POST['adv_dhcp6_id_assoc_statement_prefix_vltime'];
 
-				$wancfg['adv_dhcp6_prefix_interface_statement_sla_id'] = $_POST['adv_dhcp6_prefix_interface_statement_sla_id'];
-				$wancfg['adv_dhcp6_prefix_interface_statement_sla_len'] = $_POST['adv_dhcp6_prefix_interface_statement_sla_len'];
+				if (!empty($_POST['adv_dhcp6_prefix_interface_statement_sla_id']))
+					$wancfg['adv_dhcp6_prefix_interface_statement_sla_id'] = $_POST['adv_dhcp6_prefix_interface_statement_sla_id'];
+				if (!empty($_POST['adv_dhcp6_prefix_interface_statement_sla_len']))
+					$wancfg['adv_dhcp6_prefix_interface_statement_sla_len'] = $_POST['adv_dhcp6_prefix_interface_statement_sla_len'];
 
-				$wancfg['adv_dhcp6_authentication_statement_authname'] = $_POST['adv_dhcp6_authentication_statement_authname'];
-				$wancfg['adv_dhcp6_authentication_statement_protocol'] = $_POST['adv_dhcp6_authentication_statement_protocol'];
-				$wancfg['adv_dhcp6_authentication_statement_algorithm'] = $_POST['adv_dhcp6_authentication_statement_algorithm'];
-				$wancfg['adv_dhcp6_authentication_statement_rdm'] = $_POST['adv_dhcp6_authentication_statement_rdm'];
+				if (!empty($_POST['adv_dhcp6_authentication_statement_authname']))
+					$wancfg['adv_dhcp6_authentication_statement_authname'] = $_POST['adv_dhcp6_authentication_statement_authname'];
+				if (!empty($_POST['adv_dhcp6_authentication_statement_protocol']))
+					$wancfg['adv_dhcp6_authentication_statement_protocol'] = $_POST['adv_dhcp6_authentication_statement_protocol'];
+				if (!empty($_POST['adv_dhcp6_authentication_statement_algorithm']))
+					$wancfg['adv_dhcp6_authentication_statement_algorithm'] = $_POST['adv_dhcp6_authentication_statement_algorithm'];
+				if (!empty($_POST['adv_dhcp6_authentication_statement_rdm']))
+					$wancfg['adv_dhcp6_authentication_statement_rdm'] = $_POST['adv_dhcp6_authentication_statement_rdm'];
 
-				$wancfg['adv_dhcp6_key_info_statement_keyname'] = $_POST['adv_dhcp6_key_info_statement_keyname'];
-				$wancfg['adv_dhcp6_key_info_statement_realm'] = $_POST['adv_dhcp6_key_info_statement_realm'];
-				$wancfg['adv_dhcp6_key_info_statement_keyid'] = $_POST['adv_dhcp6_key_info_statement_keyid'];
-				$wancfg['adv_dhcp6_key_info_statement_secret'] = $_POST['adv_dhcp6_key_info_statement_secret'];
-				$wancfg['adv_dhcp6_key_info_statement_expire'] = $_POST['adv_dhcp6_key_info_statement_expire'];
+				if (!empty($_POST['adv_dhcp6_key_info_statement_keyname']))
+					$wancfg['adv_dhcp6_key_info_statement_keyname'] = $_POST['adv_dhcp6_key_info_statement_keyname'];
+				if (!empty($_POST['adv_dhcp6_key_info_statement_realm']))
+					$wancfg['adv_dhcp6_key_info_statement_realm'] = $_POST['adv_dhcp6_key_info_statement_realm'];
+				if (!empty($_POST['adv_dhcp6_key_info_statement_keyid']))
+					$wancfg['adv_dhcp6_key_info_statement_keyid'] = $_POST['adv_dhcp6_key_info_statement_keyid'];
+				if (!empty($_POST['adv_dhcp6_key_info_statement_secret']))
+					$wancfg['adv_dhcp6_key_info_statement_secret'] = $_POST['adv_dhcp6_key_info_statement_secret'];
+				if (!empty($_POST['adv_dhcp6_key_info_statement_expire']))
+					$wancfg['adv_dhcp6_key_info_statement_expire'] = $_POST['adv_dhcp6_key_info_statement_expire'];
 
-				$wancfg['adv_dhcp6_config_advanced'] = $_POST['adv_dhcp6_config_advanced'];
-				$wancfg['adv_dhcp6_config_file_override'] = $_POST['adv_dhcp6_config_file_override'];
-				$wancfg['adv_dhcp6_config_file_override_path'] = $_POST['adv_dhcp6_config_file_override_path'];
+				if (!empty($_POST['adv_dhcp6_config_advanced']))
+					$wancfg['adv_dhcp6_config_advanced'] = $_POST['adv_dhcp6_config_advanced'];
+				if (!empty($_POST['adv_dhcp6_config_file_override']))
+					$wancfg['adv_dhcp6_config_file_override'] = $_POST['adv_dhcp6_config_file_override'];
+				if (!empty($_POST['adv_dhcp6_config_file_override_path']))
+					$wancfg['adv_dhcp6_config_file_override_path'] = $_POST['adv_dhcp6_config_file_override_path'];
 
 				if($gateway_item) {
 					$a_gateways[] = $gateway_item;