# Comparison of file transfer protocols

This article lists communication protocols that are designed for file transfer over a telecommunications network.
Protocols for shared file systems—such as 9P and the Network File System—are beyond the scope of this article, as are file synchronization protocols.

## Protocols for packet-switched networks

A packet-switched network transmits data that is divided into units called packets. A packet comprises a header (which describes the packet) and a payload (the data). The Internet is a packet-switched network, and most of the protocols in this list are designed for its protocol stack, the IP protocol suite.
They use one of two transport layer protocols: the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP). In the tables below, the "Transport" column indicates which protocol(s) the transfer protocol uses at the transport layer. Some protocols designed to transmit data over UDP also use a TCP port for oversight.
The "Server port" column indicates the port from which the server transmits data. In the case of FTP, this port differs from the listening port. Some protocols—including FTP, FTP Secure, FASP, and Tsunami—listen on a "control port" or "command port", at which they receive commands from the client.
Similarly, the encryption scheme indicated in the "Encryption" column applies to transmitted data only, and not to the authentication system.

### Overview

Color key:     International standard     Internet Standard     Proposed Standard     Internet Draft :
| Protocol | Protocol | Original author | First published | Protocol suite | Standard | Refs |
| Full name | Abbreviation | Original author | First published | Protocol suite | Standard | Refs |
| Background Intelligent Transfer Service | BITS | Microsoft | 2001 | — | No | |
| BitTorrent | BT | Bram Cohen | 2001 | — | No | |
| CCSDS File Delivery Protocol | CFDP | | 2002 | — | ISO 17355:2007 (v4) CCSDS 727.0-B-5 | |
| Cross File Transfer | CFT | | | — | No | |
| Ether File Transfer Protocol | EFTP | John Shoch | 1979 | PARC Universal Packet | No | |
| Fast and Secure Protocol | FASP | Ying Xu, Michelle Munson, Serban Simu | 2007 | — | No | |
| File Delivery over Unidirectional Transport | FLUTE | Internet Society | 2004 | — | RFC 6726 | |
| File Service Protocol | FSP | Wen-King Su | 1991 | — | No | |
| File Transfer Access and Management | FTAM | | 1988 | | ISO 8571-4:1988 | |
| File Transfer Protocol | FTP | Abhay Bhushan | 1971 | Internet protocol suite | RFC 959 | |
| FTP Secure | FTPS | Internet Society | 1997 | Internet protocol suite | RFC 2228, 4217 | |
| HTTP Secure | HTTPS | Taher Elgamal et al. | 1995 | Internet protocol suite | RFC 7230 | |
| Host Unix Linkage File Transfer | HULFT | ? | 1993 | — | No | |
| Hypertext Transfer Protocol | HTTP | Tim Berners-Lee et al. | 1991 | Internet protocol suite | RFC 7231 | |
| Micro Transport Protocol | μTP | Ludvig Strigeus, Greg Hazel, Stanislav Shalunov, Arvid Norberg, Bram Cohen | 2007 | — | No | |
| Multicast Dissemination Protocol | MDP | | 1993 | | No | |
| Multicast File Transfer Protocol | MFTP | C. Kenneth Miller et al. | 1995 | — | IETF Draft (1998) | |
| NACK-Oriented Reliable Multicast Transport Protocol | NORM | | 2000 | | RFC 5740 | |
| Odette File Transfer Protocol | OFTP | Organisation for Data Exchange by Tele Transmission in Europe | 1986 | X.25 | RFC 6726 | |
| Odette File Transfer Protocol 2 | OFTP2 | Organisation for Data Exchange by Tele Transmission in Europe | 2007 | X.25, Internet protocol suite | RFC 5024 (V1.3) | |
| Reliable Blast UDP | RBUDP | Eric He et al. | 2002 | — | No | |
| Remote copy | rcp | ? | 1982 | Internet protocol suite | No | |
| Secure copy | SCP | Tatu Ylönen | 1995 | Secure Shell | No | |
| Secure Hypertext Transfer Protocol | S-HTTP | IETF Web Transaction Security Working Group | 1999 | — | RFC 2660 | |
| Simple Asynchronous File Transfer | SAFT | Ulli Horlacher | 1995 | — | No | |
| Simple File Transfer Protocol | SFTP | Mark K. Lottor | 1984 | — | RFC 913 | |
| SSH file transfer protocol | SFTP | Tatu Ylönen | c. 1997 | Secure Shell | IETF Draft (2006) | |
| T.127 | T.127 | ITU | 1995 | — | ITU T.127 | |
| Trivial File Transfer Protocol | TFTP | Noel Chiappa | 1980 | Internet protocol suite | RFC 1350 | |
| Tsunami UDP Protocol | Tsunami | Mark Meiss et al. | 2002 | — | No | |
| Tus open protocol for resumable file uploads | tus | Felix Geisendörfer, Marius Kleidl et al. | 2014 | — | No | |
| UDP-based Data Transfer Protocol | UDT | Yunhong Gu | 2004 | — | No | |
| UDP-based File Transfer Protocol | UFTP | Dennis Bush | 2001 | — | No | |
| Unix-to-Unix Copy | UUCP | Mike Lesk | 1979 | — | No | |
| Warp Speed Data Transfer | WDT | Laurent Demailly et al. | 2015 | — | No | |

### Features

The "Managed" column indicates whether the protocol is designed for managed file transfer (MFT). MFT protocols prioritise secure transmission in industrial applications that require such features as auditable transaction records, monitoring, and end-to-end data security. Such protocols may be preferred for electronic data interchange.
| Protocol | Encryption (data) | Transfer resuming | Multicast capable | Managed | Refs |
| BITS | Optional TLS / AES-128 | Yes | No | No | |
| BitTorrent | None | Yes | Peer-to-peer | No | |
| CCSDS File Delivery Protocol (CFDP) | {{{1}}} | Yes | No | No | |
| Cross File Transfer (CFT) | TLS / SSL | | | | Yes |
| Ether File Transfer Protocol (EFTP) | None | ? | No | No | |
| Fast and Secure Protocol (FASP) | AES-256 / AES-192 / AES-128 | Yes | No | | |
| File Delivery over Unidirectional Transport (FLUTE) | Optional/Unspecified | No | Yes | | |
| File Service Protocol (FSP) | None | Yes | No | No | |
| File Transfer Access and Management (FTAM) | ? | | | | |
| File Transfer Protocol (FTP) | None | Yes | No | No | |
| FTP Secure (FTPS) | TLS / SSL | Yes | No | No | |
| HTTP Secure (HTTPS) | TLS / SSL | Yes | No | No | |
| Host Unix Linkage File Transfer (HULFT) | AES | ? | No | | |
| Hypertext Transfer Protocol (HTTP) | None (see HTTPS and S-HTTP) | Yes | No | No | |
| Micro Transport Protocol (μTP) | None | Yes | Peer-to-peer | No | |
| Multicast Dissemination Protocol (MDP) | None | | Yes | Yes | |
| Multicast File Transfer Protocol (MFTP) | None | Yes | Yes | No | |
| NACK-Oriented Reliable Multicast Transport Protocol (NORM) | IPsec | | Yes | Yes | |
| Odette File Transfer Protocol (OFTP) | None | | | Yes | |
| Odette File Transfer Protocol 2 (OFTP2) | TLS | | | Yes | |
| Reliable Blast UDP (RBUDP) | None | No | No | | |
| Remote copy (rcp) | None | No | No | No | |
| Secure copy (SCP) | Secure Shell | No | No | No | |
| Secure Hypertext Transfer Protocol (S-HTTP) | CMS / MOSS / other | No | No | No | |
| Simple Asynchronous File Transfer (SAFT) | PGP | ? | No | No | |
| Simple File Transfer Protocol (SFTP) | None | Yes | No | No | |
| SSH file transfer protocol (SFTP) | Secure Shell | Yes | No | No | |
| T.127 | None | Yes | Yes | No | |
| Trivial File Transfer Protocol (TFTP) | None | No | No | No | |
| Tsunami UDP Protocol | None | No | No | No | |
| Tus open protocol for resumable file uploads (tus) | Optional/Unspecified | Yes | No | No | |
| UDP-based Data Transfer Protocol (UDT) | Experimental | No | No | No | |
| UDP-based File Transfer Protocol (UFTP) | AES-256 / AES-128 / 3DES / DES | Yes | Yes | No | |
| Unix-to-Unix Copy (UUCP) | None | Some | No | No | |
| Warp Speed Data Transfer (WDT) | AES-128 (OFB / CTR) | Yes | No | No | |
* ↑ TLS when BITS is used with HTTPS, AES-128 when used with SMB 3, none with HTTP or SMB version below 3.0
* ↑ Some implementations can obfuscate traffic using RC4 et al. See BitTorrent protocol encryption.
* ↑ RFC 6726 suggests IPSec as one option.
* ↑ One implementation, Fujitsu openFT, applies AES.
* ↑ RFC 1123 (1989) extends and corrects the provisions for restart/resume that were published in RFC 959 (1985). RFC 3659 (2007) provides for resuming in stream mode.
* ↑ It's recommended to use HTTPS provided by a webserver, proxy, or SSL terminator.
* ↑ These are the options in the reference implementation, which uses OpenSSL.
* ↑ The BNU implementation of UUCP can resume an interrupted file transfer.

### Ports

In the table below, the data port is the network port or range of ports through which the protocol transmits file data. The control port is the port used for the dialogue of commands and status updates between client and server.
The column "Assigned by IANA" indicates whether the port is listed in the Service Name and Transport Protocol Port Number Registry, which is curated by the Internet Assigned Numbers Authority (IANA). IANA devotes each port number in the registry to a specific service with a specific transport protocol. The table below lists the transport protocol in the "Transport" column.
| Protocol | Protocol | Data port | Data port | Data port | Control port | Control port | Control port | Assigned by IANA | Assignee | Refs |
| Protocol | Protocol | Server | Client | Transport | Server | Client | Transport | Assigned by IANA | Assignee | Refs |
| BITS | BITS | 80/443 / 137-139 | | TCP / UDP | | | | No | — | |
| BitTorrent | BitTorrent | 6881 | 6881 | TCP | 6881 | 6881 | TCP | No | — | |
| CCSDS File Delivery Protocol (CFDP) | CCSDS File Delivery Protocol (CFDP) | | | | | | | | | |
| Cross File Transfer (CFT) | Cross File Transfer (CFT) | 1761 | | TCP / X.25 | | | | | | |
| Ether File Transfer Protocol (EFTP) | Ether File Transfer Protocol (EFTP) | — | — | None | — | — | None | — | — | |
| Fast and Secure Protocol (FASP) | Fast and Secure Protocol (FASP) | ≥33001 | | UDP | 22 | | TCP | No | — | |
| File Delivery over Unidirectional Transport (FLUTE) | File Delivery over Unidirectional Transport (FLUTE) | 4001 | | UDP | | | | No | — | |
| File Service Protocol (FSP) | File Service Protocol (FSP) | Chosen by user | | UDP | | | | No | — | |
| File Transfer Access and Management (FTAM) | File Transfer Access and Management (FTAM) | 4800 / 102 | | TCP | | | | | | |
| File Transfer Protocol (FTP) | Active mode | 20 | 20 | TCP | 21 | ≥1024 | TCP | Yes | Jon Postel | |
| File Transfer Protocol (FTP) | Passive mode | ≥1024 | ≥1024 | TCP | 21 | ≥1024 | TCP | Yes | Jon Postel | |
| FTP Secure (FTPS) | FTP Secure (FTPS) | 989 | | TCP | 990 | | TCP | Yes | Christopher Allen | |
| HTTP Secure (HTTPS) | HTTP Secure (HTTPS) | 443 | | TCP | | | TCP | Yes | IESG | |
| Host Unix Linkage File Transfer (HULFT) | Host Unix Linkage File Transfer (HULFT) | 30000 | | TCP | | | TCP | No | — | |
| Hypertext Transfer Protocol (HTTP) | Hypertext Transfer Protocol (HTTP) | 80 | | TCP | | | TCP | Yes | Tim Berners-Lee | |
| Micro Transport Protocol (μTP) | Micro Transport Protocol (μTP) | | | UDP | | | | No | — | |
| Multicast Dissemination Protocol (MDP) | Multicast Dissemination Protocol (MDP) | Chosen by user | | UDP | | | | | | |
| Multicast File Transfer Protocol (MFTP) | Multicast File Transfer Protocol (MFTP) | 5402 | | UDP | | | | Yes | Steve Bannister | |
| NACK-Oriented Reliable Multicast Transport Protocol (NORM) | NACK-Oriented Reliable Multicast Transport Protocol (NORM) | | | UDP | | | | | | |
| Odette File Transfer Protocol (OFTP) | Odette File Transfer Protocol (OFTP) | 3305 | | TCP / X.25 | | | TCP / X.25 | | | |
| Odette File Transfer Protocol 2 (OFTP2) | Odette File Transfer Protocol 2 (OFTP2) | 6619 | | TCP / X.25 | | | TCP / X.25 | | | |
| Reliable Blast UDP (RBUDP) | Reliable Blast UDP (RBUDP) | Chosen by user | | UDP | | | | No | — | |
| Remote copy (rcp) | Remote copy (rcp) | 514 | | TCP | | | TCP | Yes | | |
| Secure copy (SCP) | Secure copy (SCP) | 22 | | TCP | | | TCP | Yes | | |
| Secure Hypertext Transfer Protocol (S-HTTP) | Secure Hypertext Transfer Protocol (S-HTTP) | 80 | | TCP | | | TCP | No | — | |
| Simple Asynchronous File Transfer (SAFT) | Simple Asynchronous File Transfer (SAFT) | 487 | | TCP | | | | Yes | Ulli Horlacher | |
| Simple File Transfer Protocol (SFTP) | Simple File Transfer Protocol (SFTP) | 115 | | TCP | | | TCP | Yes | Mark Lottor | |
| SSH file transfer protocol (SFTP) | SSH file transfer protocol (SFTP) | 22 | | TCP | | | TCP | Yes | | |
| T.127 | T.127 | 1503 | | TCP | | | TCP | Yes | Jim Johnston | |
| Trivial File Transfer Protocol (TFTP) | Trivial File Transfer Protocol (TFTP) | 69 | | UDP | | | | Yes | David Clark | |
| Tsunami UDP Protocol | Tsunami UDP Protocol | Chosen by user | | UDP | | | TCP | No | — | |
| Tus open protocol for resumable file uploads (tus) | Tus open protocol for resumable file uploads (tus) | 80 | | TCP | | | TCP | No | — | |
| UDP-based Data Transfer Protocol (UDT) | UDP-based Data Transfer Protocol (UDT) | Chosen by server | | UDP | | | | No | — | |
| UDP-based File Transfer Protocol (UFTP) | UDP-based File Transfer Protocol (UFTP) | 1044 | | UDP | | | | No | — | |
| Unix-to-Unix Copy (UUCP) | Unix-to-Unix Copy (UUCP) | 540 | | TCP | | | TCP | Yes | | |
| Warp Speed Data Transfer (WDT) | Warp Speed Data Transfer (WDT) | Chosen by server or by user | | TCP | | | TCP | No | — | |
* ↑ When used with HTTP/HTTPS, configurable
* ↑ When used with SMB
* ↑ Typically, if port 6881 is unavailable as a listening port, the peer incrementally tries 6882–6889. Another port may be specified in software.
* ↑ 1761 is the default port, but 1761–1768 are allocated by IANA.
* ↑ UDP port 21 is sometimes chosen for FSP.
* ↑ FTP was originally designed for NCP, a protocol used on ARPANET before the advent of TCP. The TCP implementation of FTP was standardized in RFC 959.
* ↑ The server listens on TCP port 21 (the control port), and the client sends commands to this port from a random port above 1023. To transfer data in active mode, the server initiates a connection from port 20 to the client at the randomly selected port number.In passive mode, the client uses a random port above 1023 as a control port, and from this initiates file transfer. The server sends or receives data from a randomly selected port above 1023, and the client sends or receives data from one port number above its own randomly selected control port.
* ↑ Can be chosen by user, but layers on top of HTTP(S) so often 80/443

## Serial protocols

The following protocols were designed for serial communication, mostly for the RS-232 standard. They are used for uploading and downloading computer files via modem or serial cable (e.g., by null modem or direct cable connection). UUCP is one protocol that can operate with either RS-232 or the Transmission Control Protocol as its transport. The Kermit protocol can operate over any computer-to-computer transport: direct serial, modem, or network (notably TCP/IP, including on connections secured by SSL, SSH, or Kerberos). OBject EXchange is a protocol for binary object wireless transfer via the Bluetooth standard. Bluetooth was conceived as a wireless replacement for RS-232.

### Overview

| Protocol | Author | First released | License | Description |
| BiModem | Erik Labs | 1989 | | Bi-directional transfers. |
| BLAST | Communications Research Group | 1981 | | Powerful protocol originating on the Data General Nova minicomputer, and then ported to micros and mainframes. |
| C-MODEM | Lavio Pareschi | 1989 | | Packet lengths from 32 to 4096 bytes, optional (but normally used) streaming mode. |
| B protocol | CompuServe | 1981 | | Offered file transfer as well as a command stream. |
| JMODEM | Richard B. Johnson | ? | | XMODEM derivative with blocks from 512 to 8192 bytes and RLE compression. |
| HS/Link | Samuel H. Smith | 1991 | | |
| Kermit | Frank da Cruz et al. | 1981 | Open Source (BSD) as of 2011 | Transport- and platform-independent transfer of text and binary files across full- or half-duplex connections with conversion of text file formats and character sets. |
| LeechModem | Sam Brown | ? | | Variations of X and Y that faked failed downloads in order to avoid BBS download quotas. |
| Lynx | Matthew Thomas | 1989 | | Similar to Kermit: 64-byte packets, 2 to 16 packets per window, CRC-32. Little or no support outside the Lynx program itself. |
| NMODEM | L. B. Neal | 1990 | | Essentially XMODEM-CRC with 2048 byte blocks. |
| OBEX File Transfer Protocol | ? | ? | | A synchronous file transfer protocol in the OBject EXchange (OBEX) Bluetooth profile. |
| OBEX Push | ? | ? | | An asynchronous file transfer protocol in the OBject EXchange (OBEX) Bluetooth profile. |
| Punter | Steve Punter | ? | | Suite of similar-but-different XMODEM-like protocols for various Commodore machines. |
| SEAlink | Thom Henderson | 1986 | | A MODEM7/XMODEM-compatible protocol with sliding window support developed to avoid propagation delays in satellite transmissions and packet networks. |
| SMODEM | Arisoft | ? | | |
| TMODEM | Mike Bryeans | ? | | |
| UUCP | Mike Lesk | 1979 | | Suite of protocols for copying files between Unix machines, used for many purposes including the distribution of email. Also allows commands to be sent, which led to the first internet worms. The file transfer protocol within UUCP is the "g" protocol. |
| MODEM7 | Mark M. Zeigler, James K. Mills | 1980 | | Slight extension of XMODEM to add filename support and batch transfers. |
| XMODEM | Ward Christensen | 1977 | Public domain | Very simple protocol that saw widespread use and provided the pattern for many following protocols. |
| WXMODEM | Peter Boswell | 1986 | Public domain | Version of XMODEM with sliding windows for higher performance. |
| YMODEM | Chuck Forsberg | 1985 | Public domain | Series of optional expansions on XMODEM for higher performance. |
| ZMax | Mike Bryeans | c. 1991 | | Modifications to ZMODEM to allow packets up to 32 kB in length. |
| ZMODEM | Chuck Forsberg | 1986 | Public domain | Streaming protocol that forsakes XMODEM compatibility but offers a wide variety of new features and improved performance. Became almost universal on BBS systems in the early 1990s. |

### Features

| Protocol | Data block size (bytes) | Data compression | Error detection | Transfer resuming | Bidirectional | Sliding window |
| BiModem | | | | | Yes | |
| BLAST | 84 - 1024+ | RLE | CRC | Yes | Yes | Yes |
| C-MODEM | 32–4096 | | CRC | Yes | | |
| B protocol | 128–2048 | | CRC32 / CRC16 / 8-bit checksum | Yes | | Yes |
| JMODEM | 64–8192 | RLE | | | | |
| HS/Link | | | CRC32 | Yes | Yes | |
| Kermit | ≤9024 (negotiated) | RLE (run length encoding, negotiated) | Checksum or CRC16 (negotiated) | Yes (binary files only, negotiated) | No | Over full-duplex only (negotiated) |
| LeechModem | | | | | | |
| Lynx | | RLE | CRC32 | Yes | | |
| NMODEM | 2048 | | | | | |
| OBject EXchange | | | | | | |
| Punter | | | | | | |
| SEAlink | | | | Yes | | Yes |
| SMODEM | | | | | Yes | |
| Tmodem | | | | No | | |
| UUCP "g" | ≤4096 | No | | No | | |
| MODEM7 | 128 | No | Checksum | | | Stop-and-wait ARQ |
| XMODEM | 128 | No | Checksum | | | Stop-and-wait ARQ |
| WXMODEM | ≤512 | | | | | Yes |
| YMODEM | 1024 | No | CRC16 | | | |
| ZMax | ≤~32,768 | | CRC32 | | | |
| ZMODEM | 256 / 1024 | No | CRC32 | Yes | | Yes |