diff --git a/wo/cli/plugins/site.py b/wo/cli/plugins/site.py
index af17533..cf6176a 100644
--- a/wo/cli/plugins/site.py
+++ b/wo/cli/plugins/site.py
@@ -889,6 +889,9 @@ class WOSiteUpdateController(CementBaseController):
                 dict(help="choose dns provider api for letsencrypt",
                      action='store' or 'store_const',
                      const='dns_cf', nargs='?')),
+            (['--dnsalias'],
+                dict(help="set domain used for acme dns alias validation",
+                     action='store', nargs='?')),
             (['--hsts'],
                 dict(help="configure hsts for the site",
                      action='store' or 'store_const',