title: Do all mainstream browsers use host headers when sending HTTP requests?
body: <p>My server is mapped to 2 domain names, and I want to return different web pages when a user is visiting the home page, based on which domain name is used.</p>
  
  <p>Django has a get_host() function in request object, Django doc:</p>
  
  <blockquote>
    <p>get_host() Returns the originating host of the request using information from the HTTP_X_FORWARDED_HOST (if USE_X_FORWARDED_HOST is enabled) and HTTP_HOST headers, in that order. If they don’t provide a value, the method uses a combination of SERVER_NAME and SERVER_PORT as detailed in PEP 3333.</p>
  </blockquote>
  
  <p>I am not sure if every mainstream browsers respect these headers.</p>
  
  <p>Can I rely on this function to tell me which domain name is the user visiting?</p>