linux - ftp passive mode

 

 

The client sends the PASV command to an FTP server on port 21. The source port is a random, high-numbered port. The destination port is 21.

 

 

 

 

 

 

 

 

 

 

 

The server responds with the PORT command. The port command specifies a random, high-numbered (ephemeral) port that the client can connect to.

 

 

 

 

 

 

The client initiates a connection to the server on this ephemeral port.

 

 

 

 

The server responds with an ACK. The FTP session has now been established