Difference between SFTP and SCP
SFTP vs SCP:
File Transfer Protocol, or FTP, is a protocol used for transferring files from one computer to another over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and uses separate control and data connections between the client and the server. FTP users may authenticate themselves using a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. When we talk about file transfer protocols, usually SFTP and SCP are normally discussed. However, there is a majority who does not understand the difference between SFTP and SCP. Therefore, this article will provide a brief explanation on differences between SFTP and SCP.
What is SFTP?
Short for Secure File Transfer Protocol, SFTP is a method of transferring files between computers over a secure SSH secure data stream. SFTP in computing terms refers to the SSH File Transfer Protocol, otherwise known as the Secure File Transfer Protocol, which is a network protocol designed to offer file management, file transfer, and file access functionality over any dependable data streams or channels. It’s also a vast improvement from its predecessor, FTP (File Transfer Protocol), which used to be the standard in file transference between two computers during the dialup era and before the broadband era. Compared to the earlier SCP protocol, which allows only file transfers, the SFTP protocol allows for a range of operations on remote files – it is more like a remote file system protocol. An SFTP client’s extra capabilities compared to an SCP client include resuming interrupted transfers, directory listings, and remote file removal. SFTP attempts to be more platform-independent than SCP; for instance, with SCP, the expansion of wildcards specified by the client is up to the server, whereas SFTP’s design avoids this problem. While SCP is most frequently implemented on UNIX platforms, SFTP servers are commonly available on most platforms. The SFTP standard was developed by the IETF (Internet Engineering Task Force) as an extension of the second version of the SSH (Secure Shell Protocol) in order to be compatible with a myriad of other protocols as well as provide users with secure file transfer capability. This specialized file transfer policy has become the gold standard in the file transferring protocol field in terms of excellence in service, security, safety, added intuitiveness, ease of use, and versatility, especially when considering the fact that it’s quite usable with other protocols too.
What is SCP?
The SCP program, which is also called as secure copy, is a software tool implementing the SCP protocol as a service daemon or client. It is a program to perform secure copying. The SCP server program is typically the same program as the SCP client. The Secure Copy (SCP) feature provides a secure and authenticated method for copying router configuration or router image files. SCP relies on Secure Shell (SSH), an application and a protocol that provide a secure replacement for the Berkeley r-tools. Perhaps the most widely used SCP program is the command line SCP program, which is provided in most SSH implementations. The SCP program is the secure analogue of the RCP command. The SCP program must be part of all SSH servers that want to provide SCP service, as SCP functions as SCP server too. Some SSH implementations provide the scp2 program, which uses the SFTP protocol instead of SCP, but provides the very same command line interface as SCP. SCP is then typically a symbolic link to scp2. The behavior of SCP is similar to that of remote copy (rcp), which comes from the Berkeley r-tools suite, except that SCP relies on SSH for security. In addition, SCP requires that authentication, authorization, and accounting (AAA) authorization be configured so the router can determine whether the user has the correct privilege level. SCP allows a user who has appropriate authorization to copy any file that exists in the Cisco IOS File System (IFS) to and from a router by using the copy command. An authorized administrator may also perform this action from a workstation. In remote-to-remote secure copy, the SCP client opens an SSH connection to the source host and requests that it, in turn, open an SCP connection to the destination. As the SCP protocol implements file transfers only, GUI SCP clients are rare, as implementing it requires additional functionality (directory listing at least).
What is the difference between SCP and SFTP?
Compared to the earlier SCP protocol, which allows only file transfers, the SFTP protocol allows for a range of operations on remote files – it is more like a remote file system protocol. An SFTP client’s extra capabilities compared to an SCP client include resuming interrupted transfers, directory listings, and remote file removal. For these reasons it is relatively simple to implement a GUI SFTP client compared with a GUI SCP client. Being operated over SSH, both are secure protocols. SFTP supports transfer resume while SCP does not support. When it comes to large files, SFTP supports files over 4GB to be transferred while SCP does not support files over 4GB to be transferred. In SFTP, ASCII transferring is supported since SFTP-4. For older versions WinSCP emulates text mode by converting files before transfer. In contrast, SCP does not suppor it. WinSCP emulates text mode by converting file before transfer. In SFTP, it is recursive operations with directories (deletion, permissions change) must be performed separately for each file. Thus operations can take a long time, especially for directories with a large number of files.
Although both SCP and SFTP utilize the same SSH encryption during file transfer with the same general level of overhead, SCP is usually much faster than SFTP at transferring files, especially on high latency networks. This happens because SCP implements a more efficient transfer algorithm, one which does not require waiting for packet confirmations. This leads to faster speed but comes at the expense of not being able to interrupt a transfer, so unlike SFTP, SCP transfer cannot be canceled without terminating the session. In SFTP Execution of arbitrary command is unsupported by the protocol. WinSCP can open a separate shell session to execute the command. In SCP it is supported as long as the command does not require user input. In the case of SFTP, It is possible to create and edit symbolic links since SFTP-3. Hard links are supported only since SFTP-6 (unsupported by WinSCP). When it comes to SCP, tt is possible to create both symbolic and hard links (ln). Symbolic links can be edited also. When it comes to file modification time-stamp, in SFTP, Theoretically the problem does not occur, as the protocol requires timestamps to be in UTC. Practically some of the SFTP servers have problems with DST. In SCP, Some shell commands are influenced by daylight-saving time. For example, the ls command can return a different time than SCP. Thus, after transfer, the time-stamp of the file can be different. Also there can be an additional difference caused by the server timezone offset. This causes trouble when comparing directories and synchronization. In the process of configuration, generally, only login information is needed for SFTP. For SCP, for a successful connection to a server it is often necessary to properly set up several configuration options on the Login dialog.