title: What does [::] mean in my nginx config file
body: <p>I was looking at my nginx config file I noticed two this.</p>
  
  <pre><code>server {
      listen 80 default_server;
      listen [::]:80 default_server;
  
      index index.html;
  }
  </code></pre>
  
  <p>I understand this part <code>listen 80 default_server;</code> it tells nginx to listen on port 80 and set that as the "default_server" but I do not understand the second line.</p>
  
  <p><code>listen [::]:80 default_server;</code></p>
  
  <p>It appears I am setting the default server again on port 80 but I do not really understand the <code>[::]</code> part of it at all.</p>
  
  <p>Can someone explain to me what this configuration does?</p>