diff --git a/sites-available/no-default b/sites-available/no-default
index 908b468..fef75fb 100644
--- a/sites-available/no-default
+++ b/sites-available/no-default
@@ -7,5 +7,6 @@
 
 server {
   listen 80 default_server;
+  server_name _;
   return 444;
 }
diff --git a/sites-available/ssl.no-default b/sites-available/ssl.no-default
index bb8be6b..78e0f94 100644
--- a/sites-available/ssl.no-default
+++ b/sites-available/ssl.no-default
@@ -7,6 +7,7 @@
 
 server {
   listen 443 ssl default_server;
+  server_name _;
   include h5bp/directive-only/ssl.conf;
   return 444;
 }