The field of computer networking has given us many technological marvels. It led to the invention of the internet, intelligent wireless communication technologies like 5G, and even upcoming technologies like IoT. All of such technologies started as experiments and evolved to become advancements that revolutionized our lives completely.
Bringing communication and networking technologies to a more advanced stage requires work on using the right strategies. Such strategies are critical to determining whether advanced communication technologies will come to life. Strategies like data transfer protocols and user authentication and authorization make technologies like the internet and IoT powerful. Many such strategies are standard, and many new ones are invented suiting the needs.
However, with so many protocols, it can get complicated for an administrator to choose from them and eventually implement them. This article goes through four of the most prominent protocols, which get frequently mixed up due to similar acronyms: SFTP, SSH, FTP, and FTPS. It will discuss how they work and what are the main differences between them.
Understanding The Different Types of File Transfer Protocols
Before diving into the main differences between all the terms, it is crucial to understand each one in its particular context. While most of them are similar and connected in one way or another, they are hardly interchangeable.
Short for File Transfer Protocol, the term is pretty self-explanatory. FTP was an unencrypted, albeit popular, mode of file transfer over a network. It is a standard protocol that enterprises can use over a private network to upload, send, and download files. The protocol is built for a traditional client-server model. It employs two data connections for its purposes: one for sending/receiving data and the other for requests and responses.
There are different flavors to FTP, briefly discussed below:
- simple and straightforward file transfer without any encryption (FTP Plain)
- transfer that uses SSL encryption for secure file transfer (FTPS)
- transfer that can operate plainly but can also be elevated to TLS/SSL (FTPES)
FTP is the most primitive form of file transfer over a network, and hence there are many security challenges associated with it. It is straightforward for hackers to intercept the data being transferred over, and the data can be stolen or modified unfavorably. Even passwords exchanged over FTP are sent as clear text rather than encrypted forms. Due to such vulnerabilities, other better protocols eventually came into existence and are used more commonly now.
As described earlier, FTPS is a flavor of FTP that employs encryption for a more secure transfer process. It supports the Transport Layer Security (TLS) and the Secure Socket Layer (SSL), which is now defunct. Like its original form, it uses more than one connection for its process and, therefore, access more ports.
FTPS itself comes in two different variants:
- FTPS Implicit SSL: Such a connection requires an SSL connection for the file transfer even to initiate. It is still in use but is favored much less than its fellow variant.
- FTPS Explicit SSL: In such a transfer, the client asks for the encryption information to know which parts of the data will be encrypted. The user can choose to send in the data unencrypted and protect their credentials or send it all in a single transfer of any kind.
Secure Shell is a network communication protocol through which computers can connect and share data. The fundamental aspect of the protocol is that all data is encrypted. It is also used to log onto remote servers and securely perform operations. SSH uses unique public key pair to authenticate the hosts. It can also automate file transfers and use them for securing management of network components.
There are many implementations of SSH, and the open-source option OpenSSH is the most widely preferred choice. It also supports SSH tunneling to open a tunnel between a local and remote host. The tunneling option can prove a robust operation for IT administrators, and they can use corporate firewalls to prevent unauthorized use.
With file transfer being so integral for all kinds of communication, a better and more secure protocol had to be derived. Along came the Secure FTP, a protocol that was a significant improvement over the previously described archaic method due to its security features. It uses the SSH encryption method and its authentication capabilities to initiate a secure connection. The protocol can be used with various graphical tools and with a command line as well.
SFTP supports file transfer along with file manipulations within its context. You can transfer remote files to your local system and vice versa as well. Additionally, many cloud services also support setting up an SFTP server on their premise. Many enterprises, which have all of their data on the cloud, often set up a server, like an AWS SFTP server, for their transferring needs.
Many commercial file transfer solutions offer SFTP solutions. Such solutions include options from technology giants like IBM to dedicated SFTP-based ones like SFTPPlus. Administrators can also automate file transfers over SFTP by using public-key authentication to automate logins. It also supports concurrent operations, and each operation is given a unique ID for better management.
The above aspects make SFTP one of the most preferred file transfer protocols used currently. Most resources tend to compare SFTP with the earlier discussed protocols to explain its better stature than them further.
Understanding The Difference Between The Protocols
With the protocols briefly described, it is now time to understand how to differentiate among them. While some fundamental differences are apparent when reading about the protocols and their workings, they are discussed more clearly below:
- Different Levels Of Security: As discussed, all of the different protocols offer varying levels of security. For example, even the FTPS, a secure form of FTP, requires more connections and more ports to be opened. However, SFTP does not require additional ports and therefore avoids any additional authentications. FTP is not secure at all at even the most basic level.
- Different Vulnerabilities: All the different protocols have different kinds of vulnerabilities associated with them. While data transferred over FTP can be modified and corrupted intentionally or even randomly due to the use of ASCII, FTPS requires more ports for connection and can lead to higher risk. SSH uses public keys, which, if overshared, can render its protection useless.
- Different Configurations: All the different protocols require different configurations as well. FTPS needs tricky firewall configurations due to its support for active and passive modes. It also requires X.509 certificate, but SFTP can use the certification method used for SSH without any additional work. SFTP only requires the SSH port for data sharing and response/request management, but it gets hard to manage SSH keys.
File Transfer Protocols Explained
All the different terms used for file transfer in the IT and networking world may sound similar but have significant differences at their ground level. Such differences need to be adequately understood if the protocols are to be used by enterprises for secure file transfer. Without a proper understanding of terms like SSH, SFTP, FTPS, and FTP, the wrong one could be used by administrators and open the crucial data to vulnerabilities.