title: how to use ftp by only one port?
body: <pre><code>listen=80
  port_enable=yes
  pasv_enable=no
  </code></pre>
  
  <p>I have set up a ftp server in my server. I want my classmates to use the ftp in the dormitory.
  But the 80 port is the only one which can be used.The port 20,21 and other ports are all unable.I tried my best to make it worked.But I failed.Please tell me how to configure the ftp with the only 80 port.Thanks :) 
  I disabled the pasv-mode.Is it right?
  My server is based on the centos. I use the vsftpd. I have shut down the iptables and seLinux.  The firewall is in front of my server. Others ports are disabled by this firewall.</p>