diff --git a/interface/web/admin/form/system_config.tform.php b/interface/web/admin/form/system_config.tform.php
index fb93fcaf4785481e8fe746dfb3e473b03120f1f9..7acd801864d3dbd6306457cd5a133ca5898f068a 100644
--- a/interface/web/admin/form/system_config.tform.php
+++ b/interface/web/admin/form/system_config.tform.php
@@ -487,6 +487,18 @@ $form["tabs"]['dns'] = array (
 			'value'  => '',
 			'name'  => 'default_slave_dnsserver'
 		),
+		'dns_external_slave_fqdn' => array (
+			'datatype' => 'VARCHAR',
+			'formtype' => 'TEXT',
+			'filters'   => array(
+					0 => array( 'event' => 'SAVE',
+					'type' => 'STRIPTAGS'),
+					1 => array( 'event' => 'SAVE',
+					'type' => 'STRIPNL')
+			),
+			'default' => '',
+			'value'  => ''
+		),
 		'dns_show_zoneexport' => array (
 			'datatype' => 'VARCHAR',
 			'formtype' => 'CHECKBOX',
diff --git a/interface/web/admin/lib/lang/en_system_config.lng b/interface/web/admin/lib/lang/en_system_config.lng
index 375aade367685cb009bdc221152d80785cd7badb..509b927955e7c6299e216c8237d678c83bd199cc 100644
--- a/interface/web/admin/lib/lang/en_system_config.lng
+++ b/interface/web/admin/lib/lang/en_system_config.lng
@@ -109,4 +109,5 @@ $wb['show_aps_menu_note_url_txt'] = 'Click here for more information.';
 $wb['dns_show_zoneexport_txt'] = 'Show zone export.';
 $wb['le_caa_autocreate_options_txt'] = 'Enable automatic creation of CAA record on issuing LE';
 $wb['show_delete_on_forms_txt'] = 'Show delete button on edit forms';
+$wb['dns_external_slave_server_txt'] = 'External DNS servers (comma separated)';
 ?>
diff --git a/interface/web/admin/templates/system_config_dns_edit.htm b/interface/web/admin/templates/system_config_dns_edit.htm
index 9636b4a26114d517adcf7c50a127401961b54fa8..0395c5b17d9da944d328bee0c48944f4272e4d7d 100644
--- a/interface/web/admin/templates/system_config_dns_edit.htm
+++ b/interface/web/admin/templates/system_config_dns_edit.htm
@@ -12,6 +12,13 @@
 	</select></div>
 </div>
 
+<div class="form-group">
+  <label class="col-sm-3 control-label">{tmpl_var name=dns_external_slave_server_txt'}</label>
+  <div class="col-sm-9">
+	<input type="text" name="dns_external_slave_fqdn" id="dns_external_slave_fqdn" value="{tmpl_var name='dns_external_slave_fqdn'}" size="" maxlength="" class="form-control" />
+  </div>
+</div>
+
 <div class="form-group">
   <label class="col-sm-3 control-label">{tmpl_var name=dns_show_zoneexport_txt'}</label>
   <div class="col-sm-9">
diff --git a/interface/web/dns/dns_import.php b/interface/web/dns/dns_import.php
index a229f3956bd097c5122763a7d991fc74a4a4323a..3b0b50ad0049311770c971fa2f29734e42d3fd8c 100644
--- a/interface/web/dns/dns_import.php
+++ b/interface/web/dns/dns_import.php
@@ -64,6 +64,8 @@ if (isset($_POST['client_group_id'])) {
 	$sys_groupid = $_SESSION["s"]["user"]["default_group"];
 }
 $domain = (isset($_POST['domain'])&&!empty($_POST['domain']))?$_POST['domain']:NULL;
+$settings = $app->getconf->get_global_config('dns');
+$external_slave_servers = $settings['dns_external_slave_fqdn'];
 
 // get the correct server_id
 if (isset($_POST['server_id'])) {
@@ -73,7 +75,6 @@ if (isset($_POST['server_id'])) {
 	$server_id = $app->functions->intval($_POST['server_id_value']);
 	$post_server_id = true;
 } else {
-	$settings = $app->getconf->get_global_config('dns');
 	$server_id = $app->functions->intval($settings['default_dnsserver']);
 	$post_server_id = false;
 }
@@ -261,6 +262,13 @@ if(isset($_FILES['file']['name']) && is_uploaded_file($_FILES['file']['tmp_name'
 			$servers[$i]['server_name'] .= ".";
 		}
 	}
+	if (!empty($external_slave_servers)) {
+		$external_servers = preg_split('/[\s,]+/', $external_slave_servers);
+		foreach($external_servers as $e) {
+			$servers[]['server_name'] = rtrim($e, '.') . '.';
+		}
+	}
+
 	$lines = file($_FILES['file']['tmp_name']);
 
 	// Remove empty lines, comments, whitespace, tabs, etc.