title: How can different subdomains point to the same IP and reach different webpages?
body: <p>I have a firebase project with 2 web applications:</p>
  <pre><code>name:      url
  PC         pc-my-app.web.app
  Mobile     m-my-app.web.app
  </code></pre>
  <p>firebase gives me the IP X.X.X.X for both applications.</p>
  <p>I have a domain, example.com with the following records:</p>
  <pre><code> A     example.com X.X.X.X
   A   m.example.com X.X.X.X
  </code></pre>
  <p>I thought that having these records pointing to the same IP would mean I see the same webpage, but that is clearly not the case.</p>
  <p>Since ports are (apparently) never specified, how can the server on X.X.X.X tell which application I am trying to connect to?</p>
  <p>My guess is that the server on X.X.X.X also recieves the original URL as a parameter somehow...</p>