title: Why Nginx welcome page is available even if I didn't run nginx?
body: <p>I've installed Nginx on CentOS7, and the Nginx welcome page is shown when I visit localhost or localhost:80. However when I restart the system, and before running Nginx, this page is also available. Why is it?</p>
  
  <p>Before running nginx:</p>
  
  <pre><code>ps -e | grep nginx
  </code></pre>
  
  <p>shows nothing.</p>
  
  <hr>
  
  <pre><code>ps -ef | grep nginx
  </code></pre>
  
  <p>shows:</p>
  
  <pre><code>username    4022 3642   0 23:28 pts/0    00:00:00 grep --color=auto nginx
  </code></pre>
  
  <p>Which I think indicates the grep command I'm using. So now Nginx is not running at all. Am I right? But now if I visit localhost page, the welcome page will show.</p>
  
  <p>After running nginx, using command # nginx:</p>
  
  <pre><code>ps -e | grep nginx
  </code></pre>
  
  <p>shows:</p>
  
  <pre><code>4159 ?    00:00:00 nginx
  4161 ?    00:00:00 nginx
  </code></pre>
  
  <hr>
  
  <pre><code>ps -ef | grep nginx
  </code></pre>
  
  <p>shows:</p>
  
  <pre><code>root    4159      1  0  23:31  ?      00:00:00 nginx: master process nginx
  nginx   4161   4159  0  23:31  ?      00:00:00 nginx: worker process
  root    4181   4113  0  23:32  pts/0  00:00:00 grep --color=auto nginx
  </code></pre>
  
  <p>I tried to search but find nothing related. I'm rather new to linux and nginx, I can't even tell the right keywords for this problem. Could someone answer this, please? Or tell me which direction should I look into to. Thanks! </p>
  
  <p>P.S. More info about this server: 
  1. I'm learning server programming to provide a simple server for my iOS game. The plan is to use python with MariaDB, Nginx on Centos 7, and use HTTP to connect.
  2. The Nginx has been installed step by step according to this page: <a href="http://nginx.org/en/linux_packages.html" rel="nofollow">http://nginx.org/en/linux_packages.html</a> I just found nginx.com seems like the real offical website. Did I use the wrong rpm?</p>