diff --git a/netjsonconfig/schema.py b/netjsonconfig/schema.py
index 5f57a210e..077f03676 100644
--- a/netjsonconfig/schema.py
+++ b/netjsonconfig/schema.py
@@ -699,7 +699,8 @@
             "propertyOrder": 5,
             "items": {
                 "title": "Domain",
-                "type": "string"
+                "type": "string",
+                "format": "hostname"
             }
         },
         "routes": {
diff --git a/tests/openwrt/test_formats.py b/tests/openwrt/test_formats.py
index 92047d413..2b1be57f4 100644
--- a/tests/openwrt/test_formats.py
+++ b/tests/openwrt/test_formats.py
@@ -73,3 +73,13 @@ def test_ntp_servers_hostname(self):
         o.config['ntp']['server'][0] = 'totally/wrong'
         with self.assertRaises(ValidationError):
             o.validate()
+
+    def test_dns_search_hostname(self):
+        o = OpenWrt({
+            "dns_search": ['openwisp.org', 'test.netjson.org']
+        })
+        o.validate()
+        # invalid hostname
+        o.config['dns_search'].append('very/wrong')
+        with self.assertRaises(ValidationError):
+            o.validate()