Problem performance:
When using FLASHFXP or passing things, you must turn off passive mode, otherwise you cannot connect, the client always prompts when connecting ftp: "PORT mode is successful, please update your site configuration file"!
Reason Analysis:
Firewall or Serv-u port with no open passive mode (PASV)
Workaround One:(connect only using port mode)
As shown in diagram settings:
Workaround Two:(you can use the PASV and Port two modes of connection)
If the server has firewall enabled, you need to open some ports on the firewall to the FTP PASV mode, otherwise you will not be able to log on using PASV mode.
First, in the Serv-u local server > Settings > Advanced > PASV port range, fill in the PASV mode used in the local port range, such as 30001-30003 must be greater than 1024, preferably the port range limited to 3, more secure.
Second, in the firewall to open this range of ports on it. (Note that multiple FTP users need to open several ports at the same time, otherwise later users will not be able to log in!) If your own server has 1 ports open