title: MongoDB VPS client_ip_address
body: <p>I'm setting up a MongoDB on a VPS that will run a Private network so that my apps on another VPS will be able to access it. I'm following the excellent Digital Ocean documentation, however, I'm not sure what <code>client_ip_address</code> is referring to. Does this mean the MongoDB VPS ip, the MongoDB VPS private network ip or the app VPS ip. 
  I'm a noob when it comes to databases.</p>
  
  <blockquote>
    <p>Next, we'll allow access to the default MongoDB port, 27017, but
    restrict that access to a specific host. If you've changed the default
    port, be sure to update it in the command below.</p>
    
    <p><code>sudo ufw allow from client_ip_address to any port 27017</code></p>
  </blockquote>