What Is SFTP?

SFTP stands for SSH File Transfer Protocol. It is a secure file transfer method that operates entirely over the SSH (Secure Shell) protocol.

SFTP is not limited to uploading and downloading files. It also supports file listing, renaming, deletion, and permission management within a secure session.

The most important feature of SFTP is that all communication between the client and the server is encrypted. This ensures that credentials and transferred files cannot be intercepted.

How Does SFTP Work?

SFTP is not a standalone service. It is a subsystem of the SSH service, which means SSH must be enabled on the server to use SFTP.

When an SFTP connection is established, the following steps occur:

• The client connects to the server via the SSH port
• User authentication is performed (password or SSH key)
• A secure encrypted session is created
• All file transfer operations occur within this encrypted channel

By default, SFTP uses the same port as SSH:

Port: 22

Key Differences Between SFTP and FTP

Although SFTP and FTP are often confused, they are technically very different.

• FTP: Transfers data in plain text without encryption
• SFTP: Encrypts all communication using SSH
• FTP: Uses separate control and data channels
• SFTP: Uses a single encrypted channel
• FTP: Vulnerable on untrusted networks
• SFTP: Secure even on public or untrusted networks

Why Is SFTP Preferred?

The primary reason for using SFTP is security. FTP poses serious risks, especially on production servers exposed to the internet.

Key advantages of SFTP include:

• Encrypted authentication credentials
• Protected file transfers
• Resistance to man-in-the-middle attacks
• Better compatibility with firewalls and NAT

Who Should Use SFTP?

SFTP is recommended for the following use cases:

• Developers managing website files
• System administrators handling servers
• Applications processing sensitive data
• Users connecting over remote or unsecured networks

Is SFTP Secure Enough?

SFTP provides a strong security foundation, but it should not be used alone. A hardened setup should also include:

• SSH key-based authentication instead of passwords
• Disabling root access for SFTP
• Firewall-based IP restrictions
• Changing the default SSH port

From a knowledge base perspective, SFTP is considered a mandatory security standard in modern server management.