diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 8aaa67e111..751d9141de 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -3611,6 +3611,9 @@
             </optional>
           </element>
         </optional>
+        <optional>
+          <ref name="alias"/>
+        </optional>
         <optional>
           <ref name="address"/>
         </optional>