diff --git a/guides/source/asset_pipeline.textile b/guides/source/asset_pipeline.textile
index 06df428cc3..9c641db964 100644
--- a/guides/source/asset_pipeline.textile
+++ b/guides/source/asset_pipeline.textile
@@ -473,6 +473,9 @@ Precompiled assets exist on the filesystem and are served directly by your web s
 For Apache:
 
 <plain>
+# the following requires mod_expires
+# on Ubuntu issue:
+# sudo a2enmod expires
 <LocationMatch "^/assets/.*$">
   # Use of ETag is discouraged when Last-Modified is present
   Header unset ETag