Allow undefined ServerName
diff --git a/apache/files/_name.conf b/apache/files/_name.conf
index 03f0dd2..4f023e9 100644
--- a/apache/files/_name.conf
+++ b/apache/files/_name.conf
@@ -2,7 +2,9 @@
   ServerAdmin {{ site.host.admin }}
   {%- endif %}
 
+  {%- if site.host is defined and site.host.name is defined %}
   ServerName {{ site.host.name }}
+  {%- endif %}
   {%- if site.host.aliases is defined %}
   ServerAlias {{ site.host.aliases|join(' ') }}
   {%- endif %}