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FTP vs TFTP: Key Differences Explained

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This article explores the distinctions between FTP (File Transfer Protocol) and TFTP (Trivial File Transfer Protocol), two application-layer protocols used for transferring files across IP networks. We’ll delve into their functionalities, commands, and the scenarios where each protocol shines.

What is FTP?

FTP, or File Transfer Protocol, is commonly used for sending and receiving files from a remote computer. Defined in RFC959, FTP establishes two connections between the client and server:

  • Control Connection: This connection handles commands and responses, managing the overall file transfer process.
  • Data Connection: This connection is dedicated to the actual transfer of file data.

FTP Authentication

FTP requires authentication via username and password. Once authenticated, you can transfer files in both binary and text formats. When a FTP client requests a connection, a TCP connection is established to the FTP server’s port 21. Post authentication, another TCP connection is established on port 20 for actual data transfer.

While GUI-based FTP applications like FTP Commander PRO and FileZilla abstract these commands, understanding them provides valuable insight into how FTP works.

FTP CommandsDescription
ftpStarts the FTP client program. You can type ftp alone, or followed by an IP address or domain name.
userChanges the user ID and password information for the current session. Prompts for username and password upon initial ftp command.
helpDisplays available FTP commands on the client.
lsLists the contents of the current directory.
asciiSwitches the FTP client to ASCII transfer mode (for text files) from the default binary mode.
binarySwitches the FTP client to binary transfer mode (for non-text files) from the default ASCII mode.
typeDisplays the current file transfer mode (ASCII or Binary).
statusDisplays current configuration settings on the FTP client.
getRetrieves a single file from the FTP server to the FTP client.
mgetRetrieves multiple files from the server.
putTransfers a file from the FTP client to the FTP server.
mputTransfers multiple files from the client to the server.
openOpens a new session with the server.
closeEnds the current session with the FTP server.
quit / byeCloses the current session and terminates the FTP client.

What is TFTP?

TFTP, or Trivial File Transfer Protocol, defined in RFC783, offers a simplified approach to file transfer. It is simpler than FTP. It provides file transfer capabilities but lacks user authentication and other advanced features found in FTP.

TFTP & UDP

A key difference: TFTP uses UDP (User Datagram Protocol), while FTP relies on TCP (Transmission Control Protocol).

Because UDP is unreliable, TFTP implements its own application-layer recovery mechanism. This involves a small header between the UDP header and the data, containing codes for read, write, and acknowledgement, along with a numbering scheme for 512-byte data blocks. These block numbers acknowledge receipt and facilitate re-sending data in case of checksum failures. TFTP sends one block and waits for acknowledgement before sending the next.

FTP vs. TFTP: A Side-by-Side Comparison

FeatureFTP (File Transfer Protocol)TFTP (Trivial File Transfer Protocol)
Port Numbers20 (data) and 21 (control)69
Transport Layer ProtocolTCPUDP
Control CommandsRobustSimple
Connection ManagementSeparate TCP connectionsConnectionless (UDP)
Memory and Programming EffortMoreLess
SpecificationRFC959RFC783
AuthenticationRequires User AuthenticationNo User Authentication

In summary, FTP provides robust and reliable file transfer with authentication and various features, while TFTP offers a lightweight and simple solution, sacrificing security and features for speed and ease of implementation.