FTP Connection Modes: Active vs Passive Mode

Below you find a step by step guide, if you prefer you can watch our FTP Connection Modes video tutorial.

While the differences between these two modes can get complex, here’s a basic explanation:

FTP and FTPS connections use two different channels to a server at once. One is used for commands and responses, the other for the actual data being transferred.

It’s a little like ordering a pizza: You make a phone call or put in an order via a website, but the actual pizza arrives by car or scooter.

The second channel – the data channel – is opened differently in active and passive modes.
In active mode, the remote server opens the data channel. In passive mode, the local machine opens the data channel using the IP address and port number with which the remote server replies to a successful connection request. Sort of like the difference between having a pizza delivered (active mode) and going to pick it up yourself (passive mode).

The reason these differences are important is that some firewalls and routers won’t allow a remote server to initiate a connection to a computer on the local network. If the remote server can’t open the data channel, the active mode FTP connection can’t transfer any data.

By default, FileZilla/FileZilla Pro uses passive mode for FTP and FTPS connections.

To see or change which mode FileZilla/FileZilla Pro uses:

  1. In the main menu, click on Edit > Settings….
  2. Select Connection > FTP from the list on the left side.
  3. Check the Transfer mode and modify if needed.
  4. Click on OK.

The video tutorial below shows how FTP Works and the differences between Active vs Passive Mode.

Video tutorial: How FTP Works

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