What is the difference between active and passive mode in FTP?

In Passive Mode, the FTP server waits for the FTP client to send it a port and IP address to connect to. In Active mode, the server assigns a port and the IP address will be the same as the FTP client making the request.

Which ports should be open for FTP?

The FTP protocol typically uses port 21 as its main means of communication. An FTP server will listen for client connections on port 21. FTP clients will then connect to the FTP server on port 21 and initiate a conversation. This main connection is called the Control Connection or Command Connection.

What is the difference between FTP port 20 and 21?

Port numbers 21 and 20 are used for FTP. Port 21 is used to establish the connection between the 2 computers (or hosts) and port 20 to transfer data (via the Data channel). But there are some instances where port 21 is used for both, establishing a connection and data transfer and I will analyse them shortly.

Why does active FTP not work with network firewalls?

FTP frequently fails when the data has to pass through a firewall, because firewalls are designed to limit data flows to predictable TCP ports and FTP uses a wide range of unpredictable TCP ports.

What is FTP passive?

Passive FTP is an FTP mode that can be requested by a client to alleviate the issues caused by client-side firewalls. Both the server and the client must support passive FTP for this process to work. When passive FTP is used, the client will initiate the connection to the server.

What is active open and passive open?

A passive open is the creation of a listening socket, to accept incoming connections. It uses socket(), bind(), listen(), followed by an accept() loop. An active open is the creation of a connection to a listening port by a client.

What are passive sockets used for?

A passive socket or acceptor socket is a type of socket that is used to wait for connection establishment requests from remote applications that communicate over the TCP protocol.