title: Why does my application's IP address not change on subsequent requests?
body: <p>As far as I know, Heroku has dynamic outbound IP addresses. But when I try to make a PHP script that requests <code>https://ipinfo.io/ip</code> via curl the IP doesn't seem to change.</p>
  
  <p>When I push new commits the IP address <em>does</em> change, and when I run <code>heroku run bash</code> and run <code>curl</code> from there I always see a new IP.</p>
  
  <p>Why does the IP not change when I run my PHP script from my browser, but it does change when I run <code>curl</code> via bash?</p>