WinSCP Technical Requirements

Using WinSCP, you can connect to an SSH (Secure Shell) server with SFTP (SSH File Transfer Protocol) or SCP (Secure Copy Protocol) service or to an FTP (File Transfer Protocol) server.

SFTP is a standard part of the SSH-2 package. SCP is a standard part of the SSH-1 package. You can also run both protocols on the latter SSH version. WinSCP supports both SSH-1 and SSH-2. For authentication, you can use user name and password or public key (RSA or DSA). Other authorization types include TIS, Cryptocard, Keyboard-interactive, and Kerberos.

For FTP, both the basic unencrypted variant and FTPS are supported. Compressed transfers (Zlib) are not supported.

For SFTP, the only requirement beyond the server requirements above is to run SFTP on the server. It is best to run it as an SSH-2 subsystem. If you select SFTP-only on the login screen and the SFTP subsystem is not found, WinSCP will try to find the SFTP server in some common directories (/usr/lib/sftp-server, /usr/local/lib/sftp-server, etc.). This way, it is possible to use SFTP even with SSH-1, which does not support subsystems.

As the SCP protocol implements file transfers only, WinSCP must use other means to implement the additional functionality (like directory listing). WinSCP uses Unix-like shell commands to do that. This in turn means that when using the SCP protocol, it can connect to servers that run Unix-like or its emulation only1.

To transfer files, scp1 is used (it is called from within scp). If only scp2 is allowed on your server, check the Use scp2 with scp1 compatibility option on the SCP/Shell tab in the Login dialog.

For correct functionality, you must do the following. The bash shell is recommended for working with WinSCP. If your default shell doesn’t work with WinSCP, you can make WinSCP use other shell.

For its operation, WinSCP needs several commands: cd, chgrp, chmod, chown, echo, groups, ls, mkdir, mv, pwd, scp, rm, ln, unalias and unset. These commands have to be placed in the path and the user must have sufficient permissions to execute them. WinSCP expects “standard” behavior of these commands. You can avoid needing these commands by not using some of the WinSCP functions (mkdir, chown, ln, etc.) or by changing some configuration options (groups, unalias and unset).

Just after establishing the connection with a server, all aliases on the above commands are cleared. This helps avoid unexpected behavior.

Another precondition is that the output of all commands be in English. This mostly concerns names of months in directory listings (ls -la). Because of this, WinSCP clears all user variables that govern command output after login. If command output also reflects some other server settings, it may be necessary to change this before WinSCP can be used.

The last necessary condition is the proper output of the ls -la command, particularly the standard number and ordering of the columns. If the default output does not satisfy the needs of WinSCP you can use Listing command option on the SCP/Shell tab in the Login dialog to modify it.

WinSCP will attempt detect support for the --full-time switch of the ls command. If the detection causes you problems, you can disable it.

A number of restricted shell environments exist for supporting SFTP/SCP only accounts. These systems restrict the user to a small subset of commands needed to manipulate files while denying the ability to execute arbitrary commands. Some of these environments create incompatibilities with WinSCP, particularly if using SCP.

Most shells nowadays offer options to make the user experience better. Unfortunately many of these options make the shell incompatible with WinSCP.

This mainly affects the SCP protocol. An example is colorized output from the ls command that includes ANSI color sequences which WinSCP cannot parse.

Also, the SFTP protocol can be affected. A typical example is where some message is printed from a start-up script. WinSCP (and any other SFTP client) will attempt to parse the message as an SFTP packet, which will obviously fail.

You should configure your start-up scripts to conform to non-interactive sessions (like WinSCP). Some shells call different profile/start-up scripts for interactive and non-interactive sessions. You can also use some environment variables, such as TERM to distinguish interactive and non-interactive sessions.

WinSCP runs on Microsoft Windows 2000 and newer, up to Windows 8/Windows Server 2012. It runs both on client and server editions of Microsoft Windows. We know of no reason why WinSCP should not continue to work on future versions of Microsoft Windows.

While there is 32-bit version of WinSCP available only, it runs on 64-bit editions of Microsoft Windows.

WinSCP also runs on Wine. See WinSCP entry on Wine AppDB.

WinSCP requires at most 15 MiB of free disk space.