>It means that the remote site cannot open a connection, it tells you which port it will use and you open the port - necessary if you use a FireWall > >excerpt from http://en.wikipedia.org/wiki/File_Transfer_Protocol > > >FTP can be run in active mode or passive mode, which control how the second connection is opened. In active mode the client sends the server the IP address port number that the client will use for the data connection, and the server opens the connection. Passive mode was devised for use where the client is behind a firewall and unable to accept incoming TCP connections. The server sends the client an IP address and port number and the client opens the connection to the server.[3] Both modes were updated in September 1998 to add support for IPv6 and made some other changes to passive mode, making it extended passive mode[5]. > > >And also > >http://slacksite.com/other/ftp.html
