The Trivial File Transfer Protocol (TFTP) is a User Datagram Protocol (UDP) and uses port 69.
In TFTP, the client sends a request to the server to read a file, write a file, or establish a connection. A file is transmitted in a fixed length of 512 bytes. A data packet of less than 512 bytes signifies the file transfer termination. Each data packet contains one data block, which helps the sender to resend the packet if the data packet is lost during transmission.
Compared with FTP, TFTP does not require complex port interactions or access or authentication control. TFTP applies when no complex interaction is required between the client and server. For example, you can use TFTP to obtain the system memory image when the system starts.
TFTP is not secure, and SFTP is recommended.