I have a ruby application that runs on a server with multiple IP addresses and mutliple vhosts. Here is the configuration of the problematic virtual host: <VirtualHost 10.0.0.10:80> ServerName realname.example.com ServerAlias alias.example.com DocumentRoot /var/www/sites/example/current/public <Directory /var/www/sites/example/current/public> AllowOverride all Options -MultiViews </Directory> ErrorLog /var/log/httpd/example_error_log CustomLog /var/log/httpd/example_access_log common RailsEnv production RackEnv production </VirtualHost> When I pull up realname.example.com the Ruby on Rails application works correctly. On the other hand alias.example.com just gives me Not Found: / I'm fairly certain the correct vhost is getting used because alias.example.com produces a 404 in the correct log file. I've tried adding logging to the Passenger config and it seems to indicate that Passenger is getting the request. Note: I can't redirect alias.example.com to realname.example.com. realname is accessed using a CDN, whereas alias is directly accessed. Anyone have any ideas why this isn't working? I've been banging my head for days and I've got a similar configuration in QA that works as expected.