Once the FTP client receives a port, it starts the second connection and sends data. Here, the client connects and sends the PASV command, which functions as a request for a port number to connect to. Passive FTP: This is also referred to as passive mode or PASV and it was developed to resolve the issue of servers initiating the connection to the client. In an Active Mode FTP, the client issues a PORT command to the server signaling that it will “actively” provide an IP and port number to open the Data Connection back to the client. In an active mode connection, when the client makes the initial connection and sends PORT, the server will then connect back to the client’s specified data port from its local data port, which is port 20. That is, when a client and server intend to transfer data, they usually start a control connection first in order to negotiate the details of the Data Connection prior to opening it and transferring data. In this mode, the FTP client connects from a random port (n-1023) to the FTP server’s command port (21). You may also want to see this guide: Warning: FTP over TLS is not enabled, users cannot securely log in: You appear to be behind a NAT Router, please configure the passive mode settings and forward a range of ports in your router.Īctive FTP: This was originally the only method of FTP and is therefore often the default mode for FTP. Before proceed with the steps on how to install and connect to an FTP Server, I will like to briefly describe the difference between active and passive FTP as this is a prevalent question when dealing with Firewall configuration to support the deployment. You may also want to see how to access FTP Server from your browser: How to create a shortcut and access Filezilla from Windows Explorer. These are port 21 for the command port and port 20 for the data port. FTP is a service that utilizes two ports, a “data port” and a “command” port (also known as the control port). To reiterate further, FTP is a TCP-based service exclusively and there isn’t a UDP component to FTP. Both server and client support FTP and FTPS, while the clients can also connect to SFTP servers. FileZilla Clients are available for Windows, Linux, and macOS, but the servers are available only in Windows. It supports TLS, the same level of encryption supported by your web browser, to protect your data. FileZilla Server is a free and open-source, cross-platform FTP application, consisting of FileZilla Client and FileZilla server that supports FTP and FTP over TLS which provides secure encrypted connections to the server.

Filezilla client web interface