title: Should you set Vary: user-agent header if using mod_rewrite based on user agent?
body: <p>I'm trying to display a differently-formatted page to mobile browsers using mod_rewrite based on the user-agent.</p>
  
  <p>If I use a rewrite condition based on the user-agent to show different content, should I also set a Vary: user-agent header? If so, how do I configure apache to do that?</p>