SFTP vs. FTPS: 7 Key Differences and Each Explained in Plain English

SFTP and FTPS are two secure protocols used for transferring files over the internet. SFTP, short for SSH File Transfer Protocol, uses Secure Shell (SSH) to establish a secure connection and encrypt data during transmission. It provides strong authentication and encryption, ensuring the confidentiality and integrity of files.

On the other hand, FTPS, or FTP over SSL/TLS, combines the traditional File Transfer Protocol (FTP) with SSL/TLS encryption. It requires a digital certificate for authentication and secures data through encryption. SFTP and FTPS differ in their underlying protocols, security mechanisms, and port numbers. Understanding these key differences is crucial in choosing the right protocol for secure file transfers.

Let’s break them down in detail below!

SFTP vs. FTPS: Side-by-Side Comparison

	SFTP	FTPS
Protocol	Uses SSH protocol	Uses SSL/TLS protocol
Port	Typically uses port 22	Typically uses port 21
Encryption	All data is encrypted, including commands	Only file transfers are encrypted
Authentication	Uses SSH key pairs or username/password	Uses SSL/TLS certificates or username/password
Firewall Friendly?	Can work through firewalls	May require additional configuration for firewalls
NAT Friendly?	Can work with Network Address Translation (NAT)	May have issues with NAT
Performance	Generally faster due to compression	Slower due to encryption and additional commands
Support	Supported by most SSH servers and clients	Supported by most FTP servers and clients

SFTP vs. FTPS: What’s the Difference?

SFTP and FTPS are secure file transfer protocols that transmit data over networks. While they may sound similar, they have distinct differences in terms of their underlying protocols, encryption methods, and port requirements.

Here are key differentiators between SFTP and FTPS, helping you choose the right protocol for your needs.

Authentication and Security

SFTP (Secure File Transfer Protocol) is a secure protocol that uses SSH (Secure Shell) to establish a secure connection between the client and the server. It provides authentication and encryption for secure file transfers. SFTP uses public key cryptography for authentication, which ensures that the client and the server can verify each other’s identity.

Authentication involves exchanging public keys and digitally signing messages to prevent unauthorized access. SFTP also encrypts the data during transit, ensuring the confidentiality and integrity of the transferred files.

FTPS (File Transfer Protocol Secure) is an extension of the FTP protocol that adds support for Transport Layer Security (TLS) or Secure Sockets Layer (SSL) encryption. It establishes a secure connection using SSL/TLS certificates to encrypt the data during transmission.

FTPS supports various authentication methods, including username/password, client certificates, and server-side certificates. It also provides data integrity checks to prevent tampering during transit.

Portability and Firewall Compatibility

SFTP operates over SSH, which typically uses port 22. Since it utilizes the SSH protocol, it can easily traverse firewalls and network address translation (NAT) devices because SSH is a well-established and widely used protocol.

Most modern operating systems have built-in support for SFTP, making it portable across different platforms. SFTP clients can connect to servers running on various operating systems, such as Windows, Linux, macOS, and Unix.

FTPS, on the other hand, requires two separate ports for communication: port 21 for control commands and port 20 for data transfers (active mode). In passive mode, FTPS uses a range of dynamically assigned ports for data transfers.

This dual-port requirement can sometimes pose challenges when dealing with firewalls and NAT devices that block or restrict certain ports. FTPS clients and servers need to be configured to use specific port ranges to ensure successful communication. Additionally, FTPS implementations may vary across different operating systems, leading to potential compatibility issues.

Protocol and Connection Mode

SFTP is an interactive file transfer protocol that allows users to perform various file operations such as upload, download, delete, and rename files on the remote server. It provides a secure and reliable channel for file transfers, making it suitable for both interactive and automated transfers.

SFTP operates in a client-server architecture, where the client initiates the connection and interacts with the server to perform file operations. The connection remains open during the entire session, enabling efficient transfer of multiple files.

FTPS, like its predecessor FTP, follows a command-response model. It supports a wide range of commands for file operations, directory manipulation, and file listing. FTPS can operate in either active mode or passive mode.

In active mode, the client initiates the data connection to the server, whereas, in passive mode, the server provides the client with the necessary details to establish the data connection. This connection mode can sometimes cause issues when dealing with firewalls and NAT devices that need to allow data connections dynamically.

Certificate Management and Flexibility

When it comes to certificate management, SFTP provides more flexibility compared to FTPS. SFTP uses SSH keys for authentication, which allows for easier key management and rotation. SSH keys are stored on the client and server sides, and the process of generating and distributing keys is straightforward.

SFTP supports various types of keys, including RSA, DSA, and ECDSA, giving users the flexibility to choose the appropriate key type based on their security requirements. Additionally, SFTP supports password-based authentication as an alternative to key-based authentication, providing further flexibility in authentication methods.

In FTPS, certificate management can be more complex. FTPS relies on X.509 certificates for authentication and encryption. These certificates are issued by a Certificate Authority (CA) and need to be obtained and installed on both the client and server sides.

The process involves generating a Certificate Signing Request (CSR), submitting it to a CA, receiving the signed certificate, and configuring the FTPS server and client to use the certificates correctly. This certificate management process can be more cumbersome and time-consuming, especially when dealing with multiple servers and clients.

NAT and Proxy Support

SFTP better supports traversing network address translation (NAT) devices and proxy servers. Since SFTP operates over SSH, which typically uses port 22, it can easily pass through NAT devices without requiring any specific configuration.

Additionally, SFTP can utilize proxy servers to establish connections between clients and servers located on different networks. This flexibility makes SFTP a preferred choice in scenarios where NAT devices separate clients and servers or when proxy servers are in use.

FTPS, especially when using active mode, can encounter difficulties when passing through NAT devices and proxy servers. In active mode, the FTPS server needs to initiate the data connection to the client, which can be problematic when the client is behind a NAT device or when using a proxy server.

NAT devices and proxies may not have the necessary capabilities to handle the dynamic nature of active mode FTPS connections. This can lead to connection failures or the need for specific configuration adjustments on the NAT devices and proxy servers to allow the data connections.

Support for File Locking and Integrity Checking

SFTP supports file locking and integrity checking, which can be beneficial in collaborative environments where multiple users are accessing and modifying shared files simultaneously. SFTP provides mechanisms for file locking, allowing users to prevent others from modifying a file while they are working on it.

This helps to maintain data integrity and prevent conflicts. Additionally, SFTP supports integrity checking through hash algorithms such as SHA-256 or SHA-512, allowing users to verify the integrity of transferred files and detect any potential tampering.

FTPS does not natively support file locking or built-in integrity-checking mechanisms. While some FTPS servers and clients may provide extensions or custom implementations for file locking, it is not a standardized feature in the FTPS protocol itself.

Similarly, integrity checking needs to be implemented separately using external tools or processes. This lack of native support for file locking and integrity checking in FTPS can be a limitation in environments that require these features for secure and collaborative file transfers.

Network Overhead and Performance

SFTP is known for its efficient use of network resources and low network overhead. It achieves this by compressing the data during transmission, reducing the size of the transferred files. SFTP also uses a single connection for the entire session, minimizing the overhead associated with establishing multiple connections for each file transfer.

Furthermore, SFTP employs optimized algorithms for data transfer, resulting in faster and more efficient transfers, especially for large files. These performance optimizations make SFTP suitable for scenarios where network bandwidth is limited or when transferring large volumes of data.

Compared to SFTP, FTPS generally incurs higher network overhead. This is primarily due to the additional complexity introduced by SSL/TLS encryption. The encryption process adds extra bytes to the transferred data, increasing the overall size of the files being transferred.

Additionally, FTPS typically requires multiple connections for each file transfer, increasing the overhead associated with establishing and maintaining these connections. The increased network overhead can have an impact on the performance of FTPS, particularly when dealing with large files or limited network bandwidth.

SFTP vs. FTPS: 8 Must-Know Facts

• SFTP (SSH File Transfer Protocol) and FTPS (FTP over SSL/TLS) are secure file transfer protocols that transfer files over a network.
• SFTP uses SSH (Secure Shell) for authentication and encryption, while FTPS uses SSL/TLS (Secure Sockets Layer/Transport Layer Security) for secure communication.
• SFTP operates on a single port (usually port 22) and provides a secure channel for file transfer, making it easier to manage firewall rules.
• FTPS requires multiple ports for its operation, including a command/control port and a separate data transfer port, which can complicate firewall configuration.
• SFTP is platform-independent and can be used on various operating systems, including Windows, Linux, and macOS.
• FTPS, on the other hand, relies on different encryption algorithms and may have compatibility issues between different FTPS server implementations.
• SFTP is known for its better security features, including strong encryption, public key authentication, and integrity checks, which help protect data during transfer.
• FTPS, while also offering secure file transfer, may have more vulnerabilities due to its older implementation and additional complexity in managing SSL/TLS certificates.

SFTP vs. FTPS: Which One is Better? Which One Should You Use?

When comparing SFTP and FTPS, both protocols have their strengths and weaknesses. However, SFTP emerges as the superior option due to its robust security features and ease of use. With SFTP, data transfers are encrypted using SSH, providing high protection against unauthorized access and data breaches. On the other hand, FTPS relies on SSL/TLS for encryption, which may introduce additional complexities and potential security vulnerabilities.

Furthermore, SFTP offers a simplified and intuitive user experience. It utilizes a single connection for both command and data transfers, eliminating the need to configure separate ports. In contrast, FTPS requires multiple port configurations, which can be cumbersome and prone to errors. This streamlined approach of SFTP enhances efficiency and reduces the risk of connectivity issues.

Another significant advantage of SFTP is its compatibility with various operating systems and firewalls. Since it operates over SSH, which is widely supported, SFTP can be seamlessly integrated into different environments without compatibility concerns. Conversely, FTPS may encounter compatibility challenges, particularly with firewalls that need to be explicitly configured to allow FTPS traffic.

Considering its superior security measures, user-friendliness, and broad compatibility, SFTP is recommended for secure file transfers. It ensures the confidentiality and integrity of sensitive data while offering a straightforward and hassle-free experience for both administrators and end-users. By opting for SFTP, individuals and organizations can prioritize data security without compromising on efficiency and convenience.