Sooner or later, every network administrator will need to transfer files from one system to another. And when they do, chances are they’ll use some form of File Transfer Protocol. Throughout the history of the Internet, several different protocols have seen the light, each successive one addressing some shortcomings of its ancestors. Today, we’re having a look at the best free SFTP and FTPS server for Windows and Linux. Why these two specific protocols? Because of security concerns. Both protocols transfer files in an encrypted fashion, making it ideal for use on public networks, such as the Internet.
But before we have a look at the actual list if the best free SFTP and FTPS servers, we’ll start off by discussing the differences between the multiple File Transfer Protocols available today. Then, we’ll introduce the best servers for Windows including a few “portable” options, i.e. servers that don’t require installation. Next, we’ll go over the best Linux free SFTP and FTPS servers.
File Transfer Protocols, What Are The Differences?
FTP is the granddaddy of all file transfer protocols. It was invented in the early 70’s as one of the primary ways of transferring files between systems. It has become so commonplace that nowadays, most operating systems–including Windows, macOS, and Linux–have some form of FTP client. FTP is an unencrypted protocol, making it less than ideal for use on public networks. This is especially true when you consider that not only the transferred files but also the login credential are unencrypted. Anyone intercepting traffic would be able to capture usernames and password. This is why SFTP and FTPS were invented.
Although it may look at first sight like SFTP and FTPS vary only by the placement of the “S”, they are actually quite different beasts. Both we developed to add security to FTP file transfers but they do it in a completely different way. Let’s see how each one operates.
The FTPS–which stands for File Transfer Protocol Secure and is also referred to as FTPES–is simply a secure version of the FTP protocol which adds an encryption layer using either the SSL (Secure Sockets Layer) or TLS (Transport Layer Security) protocols. It’s really nothing more than the FTP protocol that’s been improved to allow data encryption negotiation. FTPS was introduced in the mid 90’s shortly after Netscape released their Secure Sockets Layer extension and is now widely used. It was later improved to allow TLS in addition to SSL encryption, providing even better security.
SFTP–which stands for Secure File Transfer Protocol–is another secure way of transferring files in an encrypted fashion but it is not based on the FTP protocol but instead, on Secure SHell, or SSH. In fact, SFTP is just an extension of the SSH protocol that includes an FTP-like file transfer facility and “understands” FTP commands. As such, its security is the same as that of any SSH session.
It is important not to confuse Secure File Transfer Protocol and Simple File Transfer Protocol, both referred to as SFTP. The latter is a now-defunct protocol that was developed to be a compromise between the elementary TFTP protocol and the full-featured FTP protocol. It is no longer used but its name still exists for historical reasons.
The description of SFTP might remind you of yet another similar protocol called SCP or Secure Copy.SCP is yet another file transfer protocol that operates inside an SSH connection. This is where the similarity ends, though, as SCP only provide file transfer but has none of the advanced file management capabilities of the other protocols.
To learn more about SCP, read our recent article: Best Free SCP Servers Available for Windows, Linux and macOS.
Best Free SFTP and FTPS servers for Windows
As we’ve seen, SFTP and FTPS are very different. For that reason, not many servers will work with both protocols. Typically, FTP servers will often include FTPS capability while SSH server will allow SFTP. For each of the best servers we’re about to discuss, we’ll let you know whether they do SFTP, FTPS, or both.
1. SolarWinds SFTP/SCP Server (FREE DOWNLOAD)
You might already know SolarWinds. After all, they make some of the best network management and monitoring software. And SolarWinds as also famous for making several free software utilities. These include our number one choice, the SolarWinds Free SFTP/SCP server.
As its name implies, the server will do both TFTP and SCP. It won’t, unfortunately, do FTPS. Running as a Windows service, the server’s operation should be a no-brainer for any system admin. And if you’re new to this, its easy user interface will make you feel comfortable very quickly.
The SolarWinds free server does not use system accounts for user authentication. Instead, it uses virtual users that you create within the application for the purpose of copying files. These virtual users offer heightened security. If, for whatever reason, an account was compromised, it couldn’t be used to log into the system directly. Another feature that can improve the server’s security is that it can be configured to only allow incoming connections from specific IP addresses or ranges.
The SolarWinds Free SFTP/SCP server can be used to securely transfer files up to 4 GB in size. It can also handle concurrent transfers from multiple devices. It downloads as a zip file that extracts into a Windows MSI installer. Once installed, configuration as simple as can be. You just start its control panel application and specify a few options such as permitted protocols and transfer options.
FileZilla is probably one of the best-known FTP clients but it’s also a very good FTP server. Although the FileZilla client supports both FTPS and SFTP, the server component, which solely runs on Windows will only allow FTPS–and, of course, FTP–file transfers.
Like its client counterpart, the FileZilla server is an open-source software which can be downloaded for free and used with no restrictions. FileZilla supports the transfer of files of up to 4 GB. It also supports pause and resume. Drag-and-drop support, remote file editing, and remote file search make it simple and easy to use without compromising security.
3. Microsoft IIS FTP Server
If you’re running Internet Information Services (IIS) on your Windows server, you might not need any extra software to handle FTPS. Although IIS is primarily a web server, it also includes a built-in FTP server. And just like the web server will support both HTTP and HTTPS, the FTP server will also support FTPS.
All you need to do to use it is to add the FTP server role and create certificates. This will result in a full-featured FTPS server without having to install anything more. And since it’s part of the Windows OS, chances are it won’t cause any issues or conflicts with other software you might be running. The only limitation is that it won’t do SFTP which is based on SSH.
A close cousin of FreeSSHd, FreeFTPd is a full-featured FTP server for Windows. It is one of the rare servers that will support both SFTP and FTPS, thanks to its SSH lineage. As its name implies, FreeFTPd is a free FTP server for Any version of Windows from NT 4.0. It supports the creation of local users–rather than using Windows domain accounts.
FreeSFTP can be configured during installation to run as-needed as an application or to run as a system service. Running it as a service means that it will always be available to your SFTP users. There was a vulnerability discovered in version 1.0.11 but it was quickly fixed in version 1.0.12. Make sure the version you install is at least 1.0.12. The latest one you can download from the developer’s website is 10.0.13.
The full-featured SFTP and FTPS server from Syncplify.me is really a server on steroids. It will do much more than just server files. It was created with security in mind. One of its main features, called Syncplify.me Protector, uses artificial intelligence to automatically identify attacks. Even unknown ones.
The Server supports will run on Windows Server 2008 and up, in both 32- and 64-bit versions. Although this is a paid piece of software, there’s a free/evaluation edition which has all the features of the Ultimate edition. It will, however, only accept a single connection and it can’t be used in a production. environment.
Bitvise specializes in secure remote access software for Windows. Its primary products are the Bitvise SSH Server and SSH Client. Since SFTP is just an extension of SSH, their server will also support it. The Bitvise server is known to be one of the fastest around. Files will transfer as quickly as the client and the network connection will allow. Furthermore, an unlimited number of simultaneous connections is supported. The only real limitation you’ll encounter when using it will be that of the hardware on which it runs.
Security-wise, Bitvise leaves nothing to be desired as it uses Crypto++ 5.3, one of the best encryption libraries, to secure connections. The server also supports virtual accounts to ensure your system accounts are never exposed or compromised. The only drawback of Bitvise is that it’s not really free. It is for personal and non-commercial use but any other use required purchasing a license after a thirty-day evaluation period. At less than $100 dollars per server, the price is well worth it. They also have site licenses and worldwide limited licenses for larger organizations.
The SYSAX Multi Server supports multiple protocols. It will allow connections using both SFTP and FTPS but it will also handle FTP and HTTPS-based file transfers. And to make it even better, it’s also a telnet and SSH server. The server supports the use of both Windows accounts and locally-created “virtual” accounts. It is easy to manage and configure–even remotely–thanks to its user-friendly web-based interface.
The server is available in several different versions. The Personal edition is free but it is restricted to one connection at a time and it won’t fo HTTPS file transfers. It is also restricted to a personal or non-commercial use. There are also Standard, Professional, and Enterprise editions each supporting a few more feature that the other. Prices range from $197 to $697.
CompleteFTP Free Edition from EnterpriseDT has a full graphical user interface and it is very easy to use and configure. It will support both FTP and FTPS file transfers and has several interesting features such as support for unlimited users which is not common with free products and the creation of virtual file system to control what users can access.
Another nice feature of the product is that detailed user guides are built right into the product. you simply need to click Step-by-step guides at the top of the windows to learn how to use the different features and options. Like the previous entry, in addition to the free version, several other versions with progressively more features are also available at prices between $299 and $999. All the paid versions will, among other improvements, add support for SFTP file transfers.
The Xlight FTP server is a simple Windows FTP, SFTP, and FTPS server. It is a powerful program with low memory and CPU usage. It is designed for high performance and can handle thousands of simultaneous FTP connections. The server supports Active Directory users, LDAP users, or local users, making it a great fit in many different situations.
The Xlight FTP Server has many useful features and it has a free edition for personal use. It is limited to 5 concurrent connections whereas the Standard edition at $40 allows 50 and the Professional edition at $130 is unlimited. Note that an additional license is required for SSH and therefore SFTP. The software will run on Windows 2000, XP, Vista, 7, 10, 2003, 2008 and 2012.
Portable free SFTP servers
The next couple of entries on our list are interesting because they are portable solutions. That is, solutions that require no installation on the server computer. They can come in very handy for ad-hoc situations when you quickly need a server. You can carry it with you on a USB flash drive and always have it ready to use.
10. Syncplify.me Micro SFTP server
Syncplify.me, who brought us their full-featured SFTP and FTPS server–number 5 on our list, also offers a Micro SFTP server for Windows. Self-contained and completely portable, this SFTP server can be run from a USB stick without requiring any installation. And unlike its big brother, the Syncplify.me SFTP and FTPS server, the Micro SFTP server edition is truly free and can be used in any situation including production or commercial uses.
Of course, the software has some limitations. It only supports one user profile, one root folder, and incoming connections from one client at a time. For that reason, many use it as a test platform for SFTP client software or to test in-software file transfer features. Others use it as a personal secure file transfer server for their small home network.
11. Core Mini SFTP Server
Like the previous selection, the Core Mini FTP server is a free (S)FTP server that doesn’t require any installation. Just go to the Core FTP server’s web page to download it. Once you’ve downloaded the executable file which is available in 23- or 64-bit versions and is less than 2 Mb in size, you simply run it. You’ll need to specify the FTP username and password to be used as well as the port and root directory and you’re good to go.
Just keep in mind that the server will run with your user account and will have access to all of your files. Make sure you specify a root directory where damage by users is of no consequences. Other than that, it’s a great little server that’s easy to use albeit somewhat limited.
Best Free SFTP and FTPS servers for Linux
With Linux being open-source, it’s no surprise that there are many open-source and free SFTP and FTPS servers for the popular operating system. In fact, pretty much every distribution has an open source FTP server which, if not pre-installed, is available through the distribution’s package manager. Here are our top 3 servers.
Vsftp is a well-known free FTP server for many Unix-like systems, including Linux. It is very stable, fast, and it won’t use many systems resources. It has a long feature list which, among others, includes support for virtual users (defined locally within the server) and per-user configuration including rate limiting or throttling.
Several well-known Linux distributions use vsftp as their default FTP server. That should tell you a lot about the product’s security and stability. And for even better security, the software’s maintainer, Chris Evans, has a history of discovering security vulnerabilities.
It’s clear, when you look at its configuration file, that ProFTPd’s developers were big fans of the Apache web server. The format of the configuration file is almost identical to Apache’s. And just like Apache, it uses modules to load needed functionality. There are modules that can be added to the basic FTP server to add SFTP and FTPS capabilities.
To ease the pain of configuring the server, The ProFTPd website has several example configurations to help you get started quickly. In addition to a basic config file, there’s one for anonymous FTP, two for using virtual hosts, and one which makes use of MySQL user authentication. The software can be downloaded as a tarball from the developer’s website. Alternatively, many distributions include it as part of their optional packages.
Another great open-source SFTP server, PureFTPD not only work on Linux but also on most Unix-like operating systems such as BSD or Solaris. The project’s goal is to provide a standards-compliant FTP server. All the messages have been translated into multiple languages, making this an ideal choice for multi-lingual environments.
PureFTPD is free and comes with absolutely no limitations. all of its features are available to any user. And talking about features, we can mention the server’s ability to limit connections bandwidth, to run sessions it in a virtual file system, to set upload and or download limits, and several more great features. Pre-built packages are available for several Linux distributions including Mandriva, Debian, Ubuntu, PLD Linux, and Slackware. It’s also available as source code that can be compiled with no modification and run on any other supported OS.
15. Using OpenSSH
SFTP runs on SSH. And since SSH is built into most Linux system, SFTP is also there are ready to be used. It’s not the case for FTPS as it requires TLS libraries which are not always included. But if you have SFTP, why not use it and forget about FTPS?
On a typical Linux system, most users–as long as they have SSH access–should be able to use an SFTP client and connect to the server. That would allow them to transfer files to and from their home directory. Keep in mind that port 22–used by SFTP–could be blocked by default. You might need to dig a little to figure how to open it.
Wrapping It Up
To this day, FTP is still a very popular way of transferring files. Its lack of security gave birth to FTPS and SFTP which, although they do it in very different ways, both address security concerns. Chances are these improved protocols will still be used for years to come. Some of our top software will only do one protocol or the other while some will do both but all will do an excellent job. However, we can’t help but prefer our number one pick, the SolarWinds SFTP/SCP server as it is not only a great product but also because it is from a company that has an excellent reputation for providing some of the best network admin software including some amazing free tools.