What Port Does SFTP Use?

In today’s digital world, securely transferring files over the internet is more important than ever. Sensitive data needs protection, especially when it’s being moved between different systems or across networks. One of the most popular and reliable protocols used for this purpose is SFTP (Secure File Transfer Protocol). Understanding how SFTP works and, more importantly, what port it uses is essential for businesses and IT professionals who want to keep their data secure.

In this blog, we’ll explore the basics of SFTP, why it’s commonly used for secure file transfers, the port it operates on, and how understanding SFTP’s port usage can benefit your network security.

What is SFTP?

SFTP, or Secure File Transfer Protocol, is a network protocol that allows for secure file transfers between a client and a server. SFTP is based on the Secure Shell (SSH) protocol, which encrypts the data during transit, protecting both the files and the authentication information from potential interception.

SFTP differs from other file transfer protocols like FTP (File Transfer Protocol) and TFTP (Trivial File Transfer Protocol) because of its built-in security measures. While FTP and TFTP send data in plaintext, making it vulnerable to interception, SFTP encrypts both the data and the login credentials. This makes SFTP an ideal solution for transferring sensitive data over public or untrusted networks.

What Port Does SFTP Use?

SFTP typically uses port 22, the same port that SSH uses. This is because SFTP runs on top of the SSH protocol, leveraging its encryption capabilities for secure data transfers. Unlike other file transfer protocols that may require multiple ports to function, SFTP simplifies the process by using a single port—making it easier to manage from a network and firewall perspective.

When a client wants to connect to a server using SFTP, it will attempt to establish a connection through port 22. The server, listening on this port, will respond by initiating an encrypted session using SSH. Once this secure connection is established, the file transfer process can begin.

Why Port 22 is Important for SFTP?

The fact that SFTP uses port 22 is significant because it provides enhanced security compared to other file transfer methods. Here are some reasons why:

1. Encrypted Data Transmission: Since SFTP operates over SSH, all data transmitted through port 22 is encrypted. This protects the file contents and prevents attackers from intercepting or tampering with the data.
2. Single Port Simplicity: By using a single port for both control and data channels, SFTP reduces the complexity of network configurations. Firewalls and security appliances can be set up to monitor and restrict traffic on just one port, reducing the attack surface and making it easier to secure the network.
3. Secure Authentication: SFTP supports various authentication methods, including password-based authentication and public key authentication. These methods add an extra layer of security, ensuring that only authorized users can access the server.
4. Port Forwarding and VPN Support: Because SFTP runs over port 22, it can easily be tunneled through other secure connections, such as Virtual Private Networks (VPNs). This adds another layer of protection by encrypting the entire connection, including any data passing through port 22.

Customizing the SFTP Port

While port 22 is the default port for SFTP, it’s possible to change the port number if needed. Some organizations choose to run SFTP on a different port to reduce the risk of automated attacks or port scanning. Changing the port number can provide a basic level of security by making the service less visible to attackers. However, this is considered “security through obscurity” and should not be relied upon as the only method of protection.

To change the SFTP port, you would modify the SSH server configuration file (usually located at /etc/ssh/sshd_config on Linux systems). After specifying a new port number, the server must be restarted for the changes to take effect.

For example, to change the port to 2222, you would add the following line to the SSH configuration file:

After restarting the SSH service, the SFTP server will now listen on port 2222 instead of the default port 22. Clients connecting to the server will need to specify the new port number in their SFTP client configuration.

How SFTP Port Usage Benefits Network Security

Understanding the port that SFTP uses—port 22—can be beneficial when setting up firewalls, intrusion detection systems, and network monitoring tools. Here’s how:

1. Firewall Management: Since SFTP uses a single port, it simplifies firewall management. You can allow or block traffic on port 22 based on your network policies. Additionally, restricting access to port 22 can help prevent unauthorized connections, further securing your network.
2. Intrusion Detection: Knowing that SFTP traffic is using port 22 allows for better configuration of intrusion detection systems (IDS). These systems can monitor traffic on port 22 for any suspicious activity, such as failed login attempts or brute-force attacks.
3. Monitoring Data Transfers: Network administrators can monitor port 22 traffic to track data transfers and ensure compliance with security policies. This visibility into file transfer activity helps organizations maintain control over their data and avoid unauthorized file transfers.

SFTP in Cloud and Backup Solutions

With the increasing adoption of cloud storage and backup solutions, the role of SFTP in secure data transfer has become even more crucial. For example, many businesses that use OneDrive backup or other cloud-based services rely on SFTP to securely transfer data to and from the cloud. While OneDrive has its built-in security features, integrating SFTP for large file transfers or backups adds an extra layer of protection, ensuring data is not exposed during transit.

By using SFTP to transfer data to cloud backup services, businesses can maintain the integrity and confidentiality of their data, even when using public networks. This is particularly important for industries like finance, healthcare, and government, where data breaches can have severe consequences.

Conclusion: SFTP and Port 22

SFTP is a powerful and secure method for transferring files, made even more effective by its use of port 22. By leveraging the encryption provided by SSH, SFTP ensures that data is kept safe from unauthorized access during transit. For organizations looking to transfer files securely—whether for system updates, backups, or data migration—understanding the importance of port 22 and how to manage it is essential.

While other protocols like FTP may offer faster transfer speeds, SFTP’s focus on security makes it the preferred choice for transferring sensitive data, especially in industries where regulatory compliance is a concern. And as cloud services like OneDrive backup become more integral to modern businesses, SFTP continues to be a reliable tool for keeping data safe during transfers.