Port 20

Q: What is port 20?

FTP data transfer channel Port 20 is used by FTP (File Transfer Protocol) for the actual transfer of file data between client and server. In active mode FTP, the server initiates the data connection back to the client from port 20. In passive mode (PASV), a random ephemeral port is used for data, so port 20 is not involved. FTP transmits all data in plaintext, making it vulnerable to eavesdropping and man-in-the-middle attacks. Use SFTP (port 22) or FTPS (port 990) for secure file transfers.

FTP-DATA

FTP data transfer channel

Port

Protocol

TCP

Service

FTP-DATA

Security

Restricted

Full name: File Transfer Protocol – Data

What is port 20?

Port 20 is used by FTP (File Transfer Protocol) for the actual transfer of file data between client and server. In active mode FTP, the server initiates the data connection back to the client from port 20. In passive mode (PASV), a random ephemeral port is used for data, so port 20 is not involved. FTP transmits all data in plaintext, making it vulnerable to eavesdropping and man-in-the-middle attacks. Use SFTP (port 22) or FTPS (port 990) for secure file transfers.

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